In a direct message with the Mio app, type "channels"
Select the universal channel you want to deactivate.
Click Deactivate at the bottom of the Channel Details message.
Open the channel you chose to deactivate and click Yes. You have deactivated your channel.
If you don't see the option to deactivate a specific channel, you must contact the channel owner instead.
Find the channel owner in the same message from the Mio app from Step 1.