Open the Facebook app or go to Facebook.com and log in
Tap/click your profile picture (or menu)
Go to Settings & privacy
Select Settings
Find Blocking (or search for “Blocking” in settings)
Select View next to Blocked accounts
Locate the person’s name
Tap/click Unblock next to their name
Confirm Unblock when prompted
Refresh the page or return to the profile to verify the unblock worked