Does anyone here know exactly what was meant by Territorial Air Force members being placed onto the 'unattached list'?

I have a newspaper cutting from a pilot's collection that is gazetting the appointments and movements of various regular and territorial officers of the RNZAF. The cutting has no date on it but from matching up details of appointments with data in By Such Deeds by Colin Hanson, it seems this dates from around August 1938.

One section of the report has a long list of officers being "posted to the Unattached List" and it includes numerous well known names like Jim Hewett, Ron Sinclair, Tiny White, Ron Kirkup, Gordon Coull, Jim Mercer, Mick Wilkes, Alan Crighton, 'Johnny' Walker, Jack Busch and many others.

Does this mean they were going from the status of attending regular TAF parades to a reserve where they were no longer needed to attend regularly, but were in a reserve for the TAF or something? or does it mean they're stood down from the TAF altogether?

Most of these men were back in uniform when war broke out.