Yup, when you get to the pilot/mecha select, hit X (or whatever your have set for cancel), and it should go to a general highlight (if you get the option asking you to go back to the previous screen, you hit x too many times), from there, you should be able to scroll down over the other pilot slots, hit O to comifrm that slot, then pick the pilot/mecha, or while its highlighted in the general way (before you hit O), you can scroll left/right to select no pilot at all for that slot.