The nocking point can be changed. How depends on how it is set on your string. (See Greg's "How to tie in nocksets and a 'D' loop" post pinned at the top of this forum.) If it's a brass nockset I'd take it off and reset it with Greg's method using serving thread, but if you've got a good tune where it is and you have no clearance issues with your rest and fletching then for God's sake leave it alone!