Not sure what you're asking.
Someone who has a crush on you? Ask them, politely, to leave you alone or just avoid them if you're not good at confronting people.
How to get rid of feelings for another person? Quickest way to do that is to find someone new, I've found. They basically replace the last person. Or eat lots of Ben & Jerry's if your female cuz that's what they do, apparently(I do it to, but out of fatness and not depression)