Your designs should tell the machine to stop after a color, so you can change the thread to the next color. Your machine should have a readout showing the next color number to thread with. Just re-thread and hit the start button again. Oh, don't be afraid..you can stop the machine anytime, hit the thread cutter and thread up with a new color. But as said--the designs are digitized to stop the machine & cut the thread between color changes. Show us how it goes.