Select the channel master
This action selects the channel master of the current channel.
This action takes no parameters.
Some channels may not have a channel master, in which case the channel master cannot be selected. Also, it is possible that you are the channel master, and because you cannot select yourself, this also means you cannot select the channel master.
Instead, use the Channel > You are the channel master condition.
Attempting to select the channel master when you are the master will do nothing on Relay.
On Blue, it will set your peer selection to none, and create an error "Could not select channel master as peer: you're the channel master".