You save it as a new playlist to the second account.

1. Sign in with the account where you want to transfer the playlist;
2. Go to the playlist that you want to transfer;
3. From the playlist bar, click **Options**;<br />
![enter image description here][1]
4. Click **Save as new playlist**;<br />
![enter image description here][2]
5. Insert the (new) title of the playlist;
6. Click **Save**.

Now you have the playlist from the first account saved as a playlist of the second account.


  [1]: https://i.sstatic.net/xaMRG.png
  [2]: https://i.sstatic.net/dSTE1.png