It is my understanding that the Assignee field is used solely by VSA users and Pools (i.e. our own staff), and typically when a ticket requires input or activities performed by a 3rd party (e.g. vendor, internet provider, etc.) that would be reflected on the status of the ticket (e.g. Status = Wainting - 3rd Party).
The problem is that this only reflects that dependency while the 3rd party is performing its activities, and as soon as the ticket's status is changed to something elses (e.g. Status = Closed) there is no additional reference that this ticket was actually performed, at least in part, by a 3rd party. (and ideally, we would be able to report on the amount of time the 3rd party took to resolve the ticket).
What are the best practices or suggested approaches in order to get this information regarding 3rd party activities on a ticket?