[Q] HTC ONE M8 T-Mobile topic

Hi Friends...I need you help Urgently.

I have a T-mobile Unlocked HTC One M8 which I am using on my AT&T Sim card. I would like to remove the entire T-mobile software and would like my phone to have exactly the same software that come with a Factory unlocked phone from HTC.COM. Is it possible? If yes, please provide me step by step instructions on how to achieve it. Current S/W number is 3.32.531.2 Android 4.4.4. Also, T-mobile has blacklisted the IMEI but its working fine on AT&T. (got burnt on craiglist).

OR (if above is not possible)

Can it be converted to a AT&T Phone?

Thanks for your help in advance.

SS