About Firmware Flashing (need Help)

I have Sprint HTC One M9. And Its
Soff ed... And it has Super CID

Android Version is 5.1
Software Version is 2.6.651.11 ...

Can I install a international firmware to this Device ?
Or is there any way to convert it to international version ?

Please if you know any way to do that let me know ..

Thank you ....