The technician accounts for these users were created manually (eg: not integrated with our AD).

However, they do not have Site's populated, and there is no way to add one when you edit the technician ('Site' is not listed in the fields you can edit)

The only way I can see to do this is to convert them back to a Requester, add the Site via Admin >Requesters, and then convert them back to a technician.  I have tested this with 1 technician and it works, however this is not a very practical solution for the number I would like to edit, as I had to ensure any tickets they had assigned at the start of the process were then reassigned at the end.  Also I would have to organise downtime with multiple people in order to perform this task.

Is there any other way a Site can be added to an existing technician?

Version info:

9.2 Build 9221

(I also have access to an environment running  9.3 Build  9326, and there is still no option that I can see)