Go to your Friends list, scroll to the bottom of the page and you'll find the "Remove Friend" option. You can select the person you'd like to unfriend from the dropdown menu.

What happens if you accidentally delete the message with the pending friend request?
I did that, because I was unfamiliar with the system and was trying to move it, and when I went to see if I could friend them on their page, I didn't have the option, and they couldn't send me a friend request either.

Upon asking a mod if you can send multiple friend requests, they weren't sure so I tested it out my self. You cannot, unfortunately. Try again in a few days, it will refresh. :)

To unfriend someone, you go to Pack > Den, you click on Friends in Info and then it says Remove Friend, you select the friend you want to remove, and click submit.

Does that help? :)

Okay, so, I accidentally deleted my friends' friend request about 4 days ago. IT DOES REFRESH!
So! If anyone accidentally deletes a friend request, know that you can resend it, you just have to wait a few days!! I figured this was important to tell in case anyone else does this on accident!

You go to friends-then choose the friend you want to remove, then click submit.