1.  Go to the member's Constituent record.
  2.  Click on the Memberships tab.
  3.  Click "Renew now."
  4. The Expiration Date will automatically update. Be sure to change it to the original Expiration Date when the membership was purchased without the add-on.
  5. Change Membership Amount to $0.00 so you don't charge them again for the membership.
  6.  In the "Do they want any add-ons?" area, check the box for the Add-on they want to purchase. Update the quantity number of they are buying more than one of those add-ons.
  7.  Enter payment information and click Save.

If you would like to see the ability to sell a membership add-on outside of the renewal window added to Altru, please consider liking this idea in our community: Sell Membership Add-On without having to Renew/Upgrade Membership