Changing SIMPLE IRA from 5304 SIMPLE to 5305 SIMPLE

[M Norton]

Employer sponsors a 5304 SIMPLE, wants to change it to a 5305-SIMPLE.  There are six employees who are participating in the SIMPLE plan and all want to move to the new investment platform as a group.  (By moving as a group they will get a discount on fees, etc.)  Does the employer have to wait until January 1, 2024 to make the change?  And would he just restate on the 5305-SIMPLE?