addendum

If you’re a busy manager who uses the same contract repeatedly with multiple clients, then addendums are your BFFs. An addendum is simply any document attached to—and made part of—a contract. Using an addendum makes it easy to change schedules, prices, standards, product lists, or any other information that may vary regularly over time or from customer to customer. In some cases, the addendum is also known as a rider, an exhibit, or a schedule (although technically, the latter two terms are specific types of addendum).
How can you be sure the addendum is binding? Because an addendum is attached after the signature page, parties often initial each page of the addendum to guarantee that it will be considered part of the agreement. Another (or complementary) approach is to include the words “incorporated by reference” the first time an addendum is mentioned in a contract (for example, “The parties shall abide by the delivery specifications in the attached Addendum, incorporated by reference”). You can also use a special clause within the main body of the contract to make this point, as shown below.
EXAMPLE: Addendum. Any attached Addendums and any other attachments or exhibits to this Agreement are incorporated in this Agreement by reference.