Tap an occupied table on the floor screen and open Table Actions, and five actions sit on a single screen: Move, Merge, Split, Hand Over and Write Off. All five require the table transfer permission; a waiter without it cannot open the screen at all.
Move takes the order to another table as it is; the order number and the lines stay the same, and if the target table is occupied the program refuses. Merge transfers the lines from the source table onto the target order and closes the source with a note saying which order it went to, so the trail does not disappear. An order that has already been paid cannot be merged.
Split is the opposite: the lines you select move to a new order with its own number and its own receipt, opened on an empty table. You cannot select every line at once, because that would be a move rather than a split. A bill that walks out unpaid is closed with Write Off; a write-off never enters turnover and stands apart with its reason.