On the Axiom 61 pro you can access patch changes a number of ways.You go to edit/Global/Prog then dial up a numeric patch. When assigning a button or dial to work as a controller, DON"T use the "learn" function in mainstage. For some reason Axiom sends weird info that mainstage don't respond well to...... Jittery and jumpy response etc
Instead set Axiom's dial or button to match the cc# of the parameter you want it to control in mainstage.I find cc#'s 102 to 107 work well and haven't conflicted with anything else so far. Once you've synchronized knob/button numerically you can map it by selecting the button/slider icon in mainstage then hit map and then click on the appropriate function you wish to control.
This came from hours of trial and error. This process will also allow you to set drum pads or other buttons to correspond to particular patches.....whew...I hope that helps