Unfortunately you cannot change it but we can.  Unlike photo slideshows where the music is not part of the tour and is playing in the background and easily changeable, with video the music is embedded into the timeline and is made part of the video.  The only way it can be changed is for the video to be re-edited, recompressed and re-uploaded to the servers.  The cost to do this on Flythrough or Premier tours is $25.  For Showcase and Ultimate packages its $50.