change apple ID accounts on a mac pro

i need to change apple id account, but every time id try it says error try again later, but I have been trying for over a week

I need to change apple ID accounts on my mac, and every time I try to log out, it says error try again, but I have been trying for over a week. It also asks for old password and new password and on all the info on line that shows you how to do it they never ask this???