If you don't have too many existing macros referring to the buttons you want to rearrange and you have an inexpensive learning remote control, you should perform the rearrangement of buttons the simplest, cleanest way:

You should temporarily copy the IR frequencies to another learning remote and then copy them back (learn) to the new button arrangement you recreated on the MX-450 after deleting the old buttons you don't want.

You don't have to mess with all those macros and you don't have to waste any additional devices or additional pages.