Before he accepts it**
Removing friend request

You can't.
Yes you can. Well, you can't guarantee they won't see it or get a notification but you can cancel it. I do it all the time when I accidentally hit the button on my phone.
The easiest way is to visit their profile and click the Cancel Friend Request button.
You can also go to Share > Friends and click the Friend Requests link. Then find the member under Sent Requests and cancel there.
How can I remove a friend request I already sent before the other guy sees it?