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;
4. Click Save as new playlist;
   
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.

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;
   
4. Click Save as new playlist;
   
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.