Every store has customers that keep darting back for one more thing even after you’ve starting ringing up their purchase. If a customer does this to you and you need to move on to another sale, don’t panic! You can pause the sale and come back to it later by clicking the big orange Pause Current Transaction button in the top-right corner:
A new paused sale will appear in the top-left corner with your username and the time the sale was paused. To come back to the sale later and carry on where you left off, just click this paused sale button!