In today’s context, as the global and Vietnamese economies undergo constant changes, the adjustment of business contracts has become a common practice to ensure alignment with current developments and balance the interests of the parties. However, not all parties clearly understand the legal provisions governing clauses on modification and supplementation of business contracts. The following article by NPLaw aims to provide readers with a deeper understanding of this clause.
In today’s context, as the global and Vietnamese economies undergo constant changes, the adjustment of business contracts has become a common practice to ensure alignment with current developments and balance the interests of the parties. However, not all parties clearly understand the legal provisions governing clauses on modification and supplementation of business contracts. The following article by NPLaw aims to provide readers with a deeper understanding of this clause.
I. The importance of the clause on modification and supplementation of business contracts
The clause on modification and supplementation of business contracts serves as a key mechanism that helps maintain the validity and enforceability of the contract over time, particularly in a rapidly changing economic environment.

The importance of this clause can be seen through the following aspects:
- It creates flexibility and adaptability to the ever-changing business environment.
- It ensures the legal validity of the contract in case of legislative amendments.
- It prevents the need for renegotiation or signing of new contracts that may disrupt the parties’ business operations.
In essence, the clause on modification and supplementation of business contracts transforms the contract from a fixed document into a flexible one, protecting the parties from economic and social fluctuations while maintaining the business relationship between them.
II. Legal provisions governing the clause on modification and supplementation of business contracts
Given the crucial role of this clause, many organizations and individuals seek to understand the applicable legal provisions. However, within the complexity of the current legal system, identifying the relevant provisions is not always straightforward.
Understanding this, NPLaw provides the following overview of the concept, conditions, and key considerations when modifying or supplementing a business contract.
1. What is the clause on modification and supplementation of business contracts?
The current law does not explicitly define the term of clause on modification and supplementation of business contracts. This lack of definition may cause difficulties for those seeking to research or apply it.
Based on relevant provisions of the Civil Code 2015, NPLaw offers the following working definition: the clause on modification and supplementation of business contracts is a contractual term agreed upon and expressly recorded in the contract, allowing the parties to amend the content, obligations, or conditions of the contract after it has become effective.
This clause ensures the continued enforceability of the contract and safeguards the parties’ interests when the business environment changes.
2. Conditions for the legal validity of an agreement on modification and supplementation of a contract
Since an agreement on modification or supplementation is part of a contract, its validity is subject to the same conditions as those for a valid contract.

Article 116 of the Civil Code 2015 provides that a contract is a form of civil transaction. Therefore, for a contract to be legally valid, it must satisfy the general conditions for the validity of a civil transaction as prescribed in Article 117 of the same Code:
- The parties must have full legal capacity and civil act capacity appropriate to the transaction;
- The transaction must be made voluntarily;
- The purpose and content of the transaction must not violate prohibitions of law or contravene social ethics;
- The form of the transaction must comply with legal requirements;
- The transaction must not fall under any cases of invalidity provided by law.
In summary, for an agreement on modification and supplementation of a contract to be legally valid, it must meet the requirements regarding the parties, purpose, content, and form of the contract. A clear understanding of these conditions at the negotiation and drafting stages helps minimize the risk of contract invalidation.
3. Main considerations when modifying or supplementing a business contract
When intending to modify or supplement a business contract, organizations and individuals should take note of several important points to ensure that the revised contract remains valid and effective.
Based on practical experience, NPLaw summarizes the following considerations:
- Compliance with conditions for validity: As discussed above, the contracting parties must ensure legal capacity, lawful content, and proper form when amending or supplementing the contract.
- Authority of the signatory: The person signing the amended contract or addendum must have proper authorization; otherwise, the modification will not be legally effective.
- Consistency of contractual provisions: Newly amended or supplemented terms must be consistent with the original terms to avoid contradictions that could invalidate parts of the contract.
- Specification of the effective date: The effective date of the amendments should be expressly provided to avoid disputes.
By observing the above points, the parties can ensure that their business contracts remain legally enforceable even after modification or supplementation.
III. Questions regarding the clause on modification and supplementation of business contracts
1. Is it necessary to have the modified or supplemented business contract notarized or certified again?
If the original business contract was notarized or certified, any subsequent modifications or supplements must also comply with the same formalities (Clause 3, Article 421 of the Civil Code 2015).
2. Can a business contract be modified or supplemented via email or electronic data messages
Under Article 8 of the Law on Electronic Transactions 2023, Information in a data message shall not be denied legal validity solely on the ground that it is presented in the form of a data message.

Therefore, if the original contract was executed electronically or via email, the parties may modify or supplement it through electronic means.
3. If a contract has already taken effect, does modification or supplementation invalidate the parts already performed
Modifications or supplements only affect the amended portions from the effective date of the modification onward. The portions already performed before that time remain valid.
4. Does the law limit the number of times a contract may be modified or supplemented?
Clause 1, Article 421 of the Civil Code 2015 allows the parties to agree on contract modification. Therefore, the frequency of modification or supplementation depends on the parties’ agreement and is not legally restricted.
5. What are the legal consequences if one party unilaterally modifies the contract without the other’s consent?
Since a contract is based on mutual agreement, any modification must also be agreed upon by both parties (Clause 1, Article 421 of the Civil Code 2015). If one party unilaterally alters the contract without the other’s consent, the modified portion shall be invalid.
IV. Legal consulting services related to clauses on modification and supplementation of business contracts
The clause on modification and supplementation of business contracts plays a vital role in maintaining contract validity amid economic fluctuations.
Recognizing the importance of this clause, many organizations and individuals seek professional legal consultancy services from experienced lawyers and legal experts. NPLaw is one of the firms providing such services.
At NPLaw, clients receive professional advice from lawyers with extensive experience in contract law. We are committed to offering legal opinions that comply with current legislation.
Through this article, NPLaw has provided a comprehensive overview of clauses on modification and supplementation of business contracts. For any further inquiries, please contact us for detailed assistance.