Last weekend I took an older snapshot and rearranged the channels to make more sense. It isn't too hard, the most organized way is to save each channel to a user preset and recall them to the proper channel number:
Touch the fader for the channel you want to save.
Select "Presets".
Push "Store Preset" and name it something useful.
Unselect "Presets".
Repeat for the next channel.
Once you've saved them all:
Touch the fader for the channel you want to change.
Select "Presets".
Push the user preset you want to put there and press "Recall", "Yes".
Unselect "Presets".
Repeat for the next channel.
You'll have to go through and set the FX and aux sends correctly. You should probably go into those and write them all down first.
Don't forget to save your snapshot before looking at another snapshot or show - I had to do it all twice, about 30 minutes each as I was also changing the outputs and labels
.