NOTE: Gifts can only be linked or unlinked to the current membership record. They cannot be linked or unlinked from historic membership transactions. 

For unposted or posted gifts from the Gift record: 
  1. Open the gift
  2. Select Gift > Links > Memberships
  3. Delete the Amount Applied value
  4. Unmark the Link? checkbox
  5. Click OK
  6. Save and close the gift


For unposted gifts only from the Membership record: 
  1. Open the membership record
  2. Click View/Link Gifts
  3. Select the appropriate gift
  4. Click Break Link from the action toolbar