...which your 246T won't handle. It's not a digital trunktracker
However just to answer your question about rebanding, you need 2 things - upgraded firmware, and either entering the rebanding tables manually (which is explained at the very bottom of the link) or software (FreeScan is freeware and can do this). If you use an app to download from the database, the custom tables will be set up for you
The 246T firmware upgrade is here...be sure to follow all the instructions precisely
clarification to avoid confusion here....
Rebanded and P25 upgrade are 2 entirely different things.
Rebanding is what all 800 systems did to move frequencies around at the FCC's manadate , and that is what Sedgwick County did 2-3 years ago when they dropped all their 859.xxxx frequencies for frequencies in the 854-855 range to get away from the Sprint/Nextel channels. What they are in the process of doing right now is migrating to a P25 digital system. Has nothing to do with rebanding.