Unlinking a client from a support ticket using the API
Right now it's not possible to unlink a client from a support ticket using the API (method Update Ticket).
When the optional parameter 'userid' contains an empty string, the API code assumes the parameter was not supplied, and ignores it.
Possible solution: add a keyword that can be used as the value of the 'userid' parameter when unlinking a client from a ticket, e.g.:
This issue is confirmed by WHMCS staff, but was not accepted as a bug.