Procedure to remove F5 DNS Controller/GTM from iquery sync group, to allow maintenance?

Env: F5 LTM and GTMs at 11.5.2

In order to perform maintenance on GTMs, our thought is to remove the unit in question from the iQuery sync group, to prevent any possible impact to the gslb resolution of wide IPs involved.

Is there a procedure for doing so? I don't see anything in the Admin guide etc. docs.

Or, is there an alternate recommendation to prevent impact on DNS resolution from a GTM potentially being offline or in an uncertain state?

(Note that separately we need to prevent any DNS requests from being sent to the GTM to be removed from the sync group - i have that part sorted).

Thx!