If you want to unblock someone on Facebook, then keep in mind that a person can see your shared public posts. But, you cannot become friends automatically, and you have to send a friend request again on Facebook. Follow these steps to unblock someone.
1. Open the Facebook app on your Android phone.
2. At the top right, Tap on More.
3. Scroll down and tap on Settings & Privacy.
4. Tap again on Settings.
5. Scroll down and Tap on Blocking.
6. Here, you will find the list of blocked people.
7. Tap on unblock on the right side of the person’s name which you want to unblock.
8. In the confirmation pop-up, tap on Unblock again.
Congratulations, you have successfully unblocked a person.