Downgrade TGEA to TGE

I am a user of TGEA INDIE, but now I want to turn to the TGE INDIE because there is no available AFX & MMO Kit for the LATEST TGEA. I have to use these two tools in my project, but I could not purchase them without TGE INDIE license.

Is it possible to downgrade my license to TGE INDIE and return the price difference back? Or do not return, just turn them to something like credit that I can buy other stuffs in the future, it's even better.

Thanks!