You can change key (modulate ) as much as you like, it just depends on how you do it, and how you do it depends on how far away the key you want to move to is from the key you are working in. A simple device to use is a 2,5,1 progression. in the bar before the key change, play a minor 2 of the key you will modulate to, then the 5 chord, then the one on beat one of the next bar. So, from C major to Eb major, the last 2 bars of your sequence and the first bar of the next would look like this. C | F minor Bb7 | Eb major |