In Refersion, you can have an unlimited number of offers and affiliates. You can change the affiliate's offer at anytime by following these steps.
Go to Manage > Affiliates and look for the affiliate you're looking to update. You can scroll to find them, or search for them by clicking on the Affiliate button at the top of the list.
Next, click on the kebob menu to the right of their row, and then click Change Offer. You will see a pop-up titled "Change offer for an affiliate" where you can start typing the name of the appropriate offer. Once you select it you'll be able to click Change Offer in the pop up.
You can also update the offer from the Edit Affiliate page by going to Manage > Affiliates, clicking on an affiliate's name, and clicking on Offer & Payment.