When you send a friends request to someone, you will hope their accept your request. Unfortunately, because any reason, they don't accept immediately. Some time later, maybe they will accept, but now you don't want to be their friends. Don't worry, you can go through your pending requests and delete them.
Mobile
Step 1, tap here and go to Friend Request
Step 2, tap V
Step 3, tap View Sent Request
Step 4, choose person you want cancel friend request (here is Read Gashaea), tap Undo
Done.
Desktop
First, login to your Facebook account:
Next, click here and go to Friends Request Tab:
Finally, choose name of people you want cancel friend request ~> Friend Request Sent ~> Cancel Request