How to Fade out Music and Fade In another music smoothly?

It’s a first for me to implement a transition from music to another music. Any ideas how to make it more smother transition?

Here a sample of my code.

How about to play the music on 2 different channels and slowly decrease the volume of 1 while increase the other at the same time.
It should make a nice and smooth transition imo.

Thanks for the info!