If you have blocked somebody unintentionally or changed your mind about the block, however, it is likewise reversible. You can alter your Privacy settings to unblock and permit someone back into your Facebook world.
How To Unblock My Facebook Friend
1. Click the down arrow next to "Account" at the top right of any page on Facebook.
2. Click "Privacy Preferences" from the Account menu.
3. Click the "Edit Your Lists" link under the Block Lists heading. It is at the bottom center of the page.
4. Click the "Unblock" link beside the name of the individual you wish to unblock. A list of individuals you've obstructed is discovered under the Block Users area.
Suggestion
Uncloging somebody does not automatically put that person back in your friend list. You must add the recently unblocked individual as a pal and await them to confirm the demand.
And one more thing please don’t forget to share this awesome trick to use the How To Unblock My Facebook Friend with your friends.