If you have an iPhone app, you can reset your HM-6 by either:
1. Unplug and plug your battery into the electronics.
2. Perform a soft reset via the Device Reboot function.
3. Perform a hard reset via the Factory Reset function. Factory Reset will delete the data in your phone (but not the data in the cloud so be sure to upload your data before performing a Factory Reset, if you can)
To access the Device Reboot or Factory Reset functions:
1.) Tap on the "circled i".
2.) Tap on "HM6 Settings"
3.) Tap on "Device Reboot" or "Factory Reset".