What happens to the centre of pressure on a symmetric aerofoil before and after stall?
As PBL says, your question is rather imprecise - you need to specify how much after the stall.
Check out NACA Report 460 - you may be able to find it on line - I did but I can't remember where! Any problem PM me and I will send you a copy - I presume you have a standard UB mail address?
I assume also that you are talking about two dimensional sections rather than complete wings?
Basically the CoP moves from 25% chord with attached flow back to somewhere in the region of 30 to 40% chord at about 30 deg AoA, the thicker the airfoil the less it moves. NACA 0006 for example moves to 40%, NACA 0025 to just over 30%
You can't tell where the CoP is just by looking at a table of pressure distribution - you have to do the hard work of integrating the local Cps and calculating the lift and pitching moment about your chosen reference.