In situations that require more than a limited waiver or limited consent, a treaty amendment may be appropriate. If you change a contract, change the original contract in some way. This may include adding, deleting or correcting parts of the contract. Treaty amendments do not replace the whole treaty, but often replace part of it. You can use a separate document to define how to edit an entire section. You should note at the beginning of the document which part will be modified and when it will be effective. Here too, both parties should sign or initialize the amendment and date it to show that both parties have accepted the amendment. Creating this separate section is usually the easiest way to clearly modify your contract, and it can avoid the misinterpretations that are sometimes associated with the other two methods. For example, if you tried to change your agreement by adding a new clause that says, “Anyone who bought things from our store two years ago agrees to pay us $10,000,” that would not apply. You may not modify the terms of an agreement a posteriori, even if you terminate it appropriately and continue to use the service. For all kinds of changes, add that only the referenced sections will be replaced and everything else in the original contract will remain as it was.
For example, the author may write, “All other terms that have not been modified by this or previous modifications remain in full force and effect.” Ensure that all parties sign and date the change. The parties may, if necessary, call on witnesses or record the modification notarized. Make copies available to all parties as soon as they are signed. . . .