If you want to stay friends but hide personal updates, add them to your Restricted List. They will only see your posts marked as "Public" or posts you tag them in directly.
If you prefer using Facebook on a computer (or you’re at work trying to fix a social mistake), here’s how: unblock a person on facebook
Since its inception in 2004, Facebook has evolved from a university directory into a primary architecture for social interaction. Within this architecture, the ability to "block" a user serves as the ultimate boundary mechanism, rendering a user invisible and inaccessible. However, the reciprocal action—"unblocking"—represents a complex social maneuver. If you want to stay friends but hide
The architecture of Facebook forces a "sunk cost" element to the decision. Because re-blocking is delayed by 48 hours, the user must trust that the unblocked party will not act maliciously during that window. This vulnerability is the price of re-entry into the social graph. Within this architecture, the ability to "block" a
Tap your (with three horizontal lines) in the corner of the screen.