If you have blocked somebody inadvertently or altered your mind about the block, though, it is likewise reversible. You can change your Privacy settings to unblock and permit somebody back into your Facebook world.
How To Unblock Someone In Facebook
1. Click the down arrow beside "Account" at the leading 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 "Unclog" link beside the name of the person you want to unblock. A list of individuals you have actually obstructed is found under the Block Users area.
Suggestion
Uncloging someone does not instantly put that person back in your pal list. You should add the freshly unblocked person as a pal and wait on them to verify the request.
And one more thing please don’t forget to share this awesome trick to use the How To Unblock Someone In Facebook with your friends.