A real estae contact must be cancelled by the broker and it must be unconditional. If that didnt happen than the second realtor should not have taken the listing. The second realtor should have made sure all "ducks" were in a row and asked to see paperwork that proved you were able to list w the second realtor.
If the first realtor doesnt let you out of the listing you can 1) call his broker, 2) call the board of realtors and explain why you want a release 3) not show your property while listed with the first realtor and let the time run out.
I dont know what happened that you changed your mind but you just cant switch unless you have the above signed releases. Good luck.... more