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 type in the affiliate name and click search.
Next, click on their current offer. You will see a Modify Offer pop-up, choose another offer from the Change Offer dropdown and click Update. You can always create a new offer from the Manage > Offers page.
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.