If the layout builder did not include a channel changer control, then the brute force method is to edit each control to (1) the new channel, or (2) to a supercontrol channel changer.
However, a single StreamByter output rule can remap everything to a different channel.
Replace 0 to F for channels 1 to 16 in the second position.
X0 = X2 # remap all channel 1 messages to channel 3
p.s, after checking that the code works on the referenced layout, appears most of the controls are sysex, not channel specific message. Believe there are only three channel specific, so it would not be involved to add a channel changer to the layout.