Hello - we live in Southern California and my daughter would like to visit a friend in Dallas for a few days and then a friend in NYC for a few days, and then fly home from NYC. Is there a way to do this with a multi-day layover in Dallas, or do I have to book her a bunch of one-ways?

Would prefer Delta as she has a voucher to use with them, but open to other airlines if there is a way to make it work. I also usually prefer to book directly with the airline vs a third party...but I'm not seeing a way to make it happen with a round trip.

Thanks!