You will need
  • The contract
The supplementary agreement is intended to modify or to terminate the contract. So before you make the agreement, carefully read all the provisions of the main contract, its essential terms. We must remember that the supplementary agreement is in one of the following cases:

- is the mutual desire of the parties to the contract,

- at the request of one of the parties, if required by law or by contract,

- if one of the parties refuses to execute the contract and such refusal is permitted by law or contract.

Form of the additional agreement - the same as the basic form of the contract. That is, if the main contract in a simple written form, and an additional agreement made in written form. If the main contract is passed the state registration or have been notarized, the supplementary agreement shall also be subject to these procedures. If you break this rule, a supplementary agreement will be void.
In the preamble of the supplementary agreement must specify the time and place of conclusion, surname, name, patronymic, and position of the signatories. It should be remembered that many of the parties were in basic agreement that must be in the supplementary agreement, unless the agreement specified otherwise. The agreement shall enter into force from the moment of signing (unless otherwise specified in the agreement, the contract or the law), so it is important to specify the date.

Do not forget to specify under what document the signer is valid. This can be power of attorney, notarized, or the Charter of the enterprise. If the signatory is a physical person in his behalf, such document need not be specified.

Be sure to include, additional agreement to what exactly the contract is made.
Specify in the text of the additional agreement, in which part of the updated, changed, or terminated the main contract. Specify all of the provisions, which must be reached agreement.
An additional agreement be signed by the persons who have signed the main contract, or persons in Loco parentis. The signatures are held together by side seals, if these seals are to be determined. For example, a person who is not an individual businessman, has no printing.