If you need to replace an existing Order Form with a new one after a contract term has already started, you can have the customer sign a new Order Form and add the following to the contract notes section:
The parties acknowledge and agree that, as of the Effective Date set forth above, this Order Form supersedes and replaces the existing Order Form entered into by and between the parties with an Effective Date of [INSERT EFFECTIVE DATE] (the “Existing Order”), which is hereby terminated. For any Services under the Existing Order that have been paid for but remain undelivered as of the Effective Date set forth above, Gem will issue a pro-rated credit in an amount equal to [$___] to Customer that can be applied to any unpaid invoice under this Order Form.
If no credit is being issued because they have not yet paid any associated invoices, the last line with the credit amount can be removed.