Before you do anything, create a folder (I call original) Open maintenance and read tracking and features.
Save this to your new folder.
Now if RPM 14 will read your radio, save the '.PRS' also to the new folder.
If you get a version error, you will need RPM 10b to do this. ( gives you something for recovery if all fails)
14 should still accept your .PRS file. Use 'maintenance' .Read the tracking data from the radio.
Go to edit tracking data and select 'POWER LEVELS'
The decimal range is 200 for max. You can leave those at default.
There is no mid power so in 'low power', set what you want for low power. first two digits and zero.
Now set 'high power for '600'
Write the new tracking to the radio. Save this to a current 'active' folder.
Now with the radio through a watt meter/dummy load and a 2 meter frequency, confirm your low and high power is set correctly. A service monitor is a plus, you can check your frequency and wideband deviation at this time.
If all looks good, you are ready to burn holes in the ether.
This shot is one of my M7100s before reducing the power levels.
Note: this is two year old memory so may not be exact, anyone with corrections, please chime in.