What bandsplit is it already? 150 to..whatever?
You MIGHT be able to read the tracking data via the radio maintenance tools, and edit the tracking data
to change the bandsplit, and then write the modified data to the radio. Then you should be able to read your radio, make changes, and write back to the radio. It should work.
Most GE radios are pretty mild mannered about having their bandsplit shifted over. Some won't do it,
but most will.
Elroy