howto chance carrier from tmobile

If you want to leave you need to request a port out of Tmobile if you want to port in to Tmobile you do the same thing.

you can also contact whichever other carrier you are looking at and ask them what all you need to do on your side and what all they will handle on their side.

If you're trying to manually roam on another carrier … good luck.  There are settings on the device for manual network carrier selection, but you may find that they might not connect.  I did manually change carriers in Northern Maine from AT&T roaming (default) to USCellular.  Speed went from 256kbps to 3Mbps.