The option to update playlists

After loading a play list and fine tuning it by adding and deleting tracks It would be nice to have the option to update the current play list rather than creating a new one and then deleting the old.

Related request to the Queue: As a listener playing a new album that I have just purchased or an old playlist that I have not played in a while, when I hear a few songs that I would like to move to a different but existing play list, I would like to have the ability to add these songs right from the Queue. Right now, I would have to remember the songs that I want to move, then navigate away from the Queue to the Album or Artist or Playlist that contains the song, then select these songs to add to the playlist.