Changing or adding playlists is not possible once your campaign has been scheduled and paid for. Please be 100% sure of your selections.
Targeting different playlists requires running another campaign targeting and sending the song out again.
How to adjust targeting on a rerun:
If you want to target additional playlists, you can do this after your campaign ends by setting up a campaign rerun. This is a great option for expanding your reach and building on the momentum of your first campaign.