swap (switch) horses in midstream
To change leaders or adopt a different strategy in the middle of a course of action: “When the coach was fired just before the playoffs, many thought it was a bad idea to swap horses in midstream.”
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.