The conversation between human and AI assistant.
How can we set a piece to 3/4 or 6/8 time signatures on Garageband? 
I understand. Can I change the time signature midway through my piece?
Yes, you can absolutely change the time signature in the middle of your piece. Just go to the Control menu, select "Time Signature," and choose the new time signature you want to use. The change will seamlessly transition in your composition.