With CC you gain access to all compatible versions and you may install legacy versions at any point. nothing gets ever removed other than for technical reasons or cessation of support. The rest is unclear. I'm not even sure what a "free subscription" is supposed to mean. If you are getting your license via your school or something like that, then there is no need to cancel anything even since it's part of a managed license pool. If it's something else, you need to explain.