That's a yes to the first part of your question. Once there's a committal, you can't withdraw the authority to proceed, but the minister still has the power to end the proceedings by discharging at his stage. The withdrawal of the authority to proceed is handled by officials, and that's prior to the committal decision. Then, once there has been a committal decision, the minister is making a decision on surrender. His decision could be to surrender or to discharge, and a discharge would bring the proceedings to a close.
On February 4th, 2020. See this statement in context.