Add an additional breakout room during a meeting

Hello! I work for an MSP, and a client of ours uses Zoom a great deal. She recently tried to add an additional room to a meeting that was in-progress, and nothing happened when she clicked on the Breakout Room icon. I have read a couple of support articles that seem to indicate that it is possible to add additional rooms, but a co-worker told me the only way to do this with a meeting that has begun is to close the current rooms, then re-create them plus the additional room. Is this true?  Thanks!