You used to be able to do this. Why would you want to revoke one? Just don't send it in the first place.
If it is accepted, and you don't want to be friends with that person you can delete them off your friends list.
When I quit, I don't want anyone on my friends list.
I don't want to have 1 random 9 year old I sent a friend request to 2 years ago the only one on the list.