Are you looking to be cross-trained or promoted? There's a huge difference.
This week we had a cashier accidentally get in line for cross-training. There was a back up over in Starbucks, and my cashiers weren't busy, so I sent the cashier over who I knew could be a good help. She protested that she didn't know what to do. I told her anyone could rinse dishes and the TL would give her direction. By the end of that wave of guests, she was ringing up orders over there under the direction of the TL. Next thing we know, they got to talking, and the TL asked her if she was interested in learning it, and she's already had her first training shift in food ave.