In Perform Mode, you should see “HS1 ON” or “HS1 OFF”. Most of the factory programs have the hot switches assigned to the 2nd page of performance parameters. Press the Perform knob twice and you should see the hot switches, and see what the UI looks like toggling them on/off. Also, the LEDs will be blue when a Hot Switch is off and red when a Hot Switch is on.

You can use the momentary bypass CC message with a CC value of 63 or less to bypass the Hot Switch and 64 or greater to activate the Hot Switch. The tip in this section of the manual explains this for active/bypass, it also applies to Hot Switches. https://cdn.eventideaudio.com/manuals/h90/1.7.1/content/appendix/global.html