- Go to Constituents profile of the constituent in question
- Under memberships, click their membership's hyperlink.
- Click "Renew now"
- Change the expiration date back to what it was originally (when the membership was purchased without the add-on).
- Change membership amount to $0.00 so as not to charge them for the membership again.
- Add the add-on
- Enter payment information and 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