Hi Glen,
You should have no problem at all.
If you elect to keep your music files in both locations, I believe the next time you launch iTunes it will sense that you have two locations and ask which library you'd like to use.
If you move your files to the new drive and delete them from the other partition, iTunes will prompt you with the same question.
At that point, All you have to do is choose the new folder and you're good to go!
Have fun!
You should have no problem at all.
If you elect to keep your music files in both locations, I believe the next time you launch iTunes it will sense that you have two locations and ask which library you'd like to use.
If you move your files to the new drive and delete them from the other partition, iTunes will prompt you with the same question.
At that point, All you have to do is choose the new folder and you're good to go!
Have fun!