I always recommend that you leave the request pending as well. Certain people send them to everyone and don't track who they've sent requests to, so when they see someone isn't already their friend, and doesn't have a request pending, they send one.
I you really can't bear the idea of leaving it pending, you can also accept it, send a message that you'd rather not be friends, but thanks, and ask them to stop sending requests. Then, unfriend them. If they ask again, it constitutes stalking/ harassment, but I'm not going to assume that's the case unless the person has been explicitly told to stop friend requesting you and I have evidence of the cease and desist order as well as the request after.
As a last option, you can email me privately and let me know who it is and I'll talk with them. If they send you another request after that, leave it pending and notify me. After I have seen it, I will take administrative action. Personally, I prefer that you try to handle it on your own, either by leaving it pending or talking to the person, but I'll step in if I need to.
If you'd like me to follow up administratively, please email me, and then leave all future contact the person makes with you intact.
If you're referencing the person I think you're referencing, I have never seen him delete and resend a request, nor has he ever made any kind of contact with an individual after being asked to stop. As far as I know, the methods I discussed are effective with this particular person. However, if you have evidence to the contrary that shows you spoke to the person and told them to stop, and you have a new pending request, let me know and I will follow up.
JA, there have been numerous discussions in the past about this particular person continually sending requests even after being asked to cease.
I intend to send him another message asking him to stop and will let you know if it continues. When I've sent messages to him in the past, I haven't done screen shots, so I have nothing to send you. I do recall posting at least one message directly on his page
Will you be my friend? 
No. 
WM BARR . =ABSOLUTE TRASH 