Say I applied to two graduate programs: A and B, in which A is my preferred program. It turns out that I am admitted by both, so I will accept the offer from A and turn B down. I heard from a friend that in this case, I may "refer" the offer from B to someone I know who is waitlisted by B so that s/he can be admitted to B.
Is this practice common in the US? Additionally, can I refer the offer to someone who has been rejected? Searching online just gives me pages of results about "referral programs", which aren't very relevant.