You can allocate a new Audit File and then simply run TMSINIT to point to the new Audit File at any time. That has nothing to do with the CTS address space. We even document how to allocate and switch to a new Audit File without having to stop tape processing in the online documentation;
https://techdocs.broadcom.com/us/en/ca-mainframe-software/performance-and-storage/ca-1-tape-management-system/14-0/utilities-and-reports/tmsformt-utility-format-extend-the-tmc-and-audit-data-set/formatting-the-audit-file-without-shutting-down-tape-processing.html
If you want to start using the CTS address space; that is fine. But that is completely un-related to the moving or re-allocating an AUDIT file.