Not really sure what you are asking.
To complete a help desk ticket, set the Status to "Closed".
If you mean the process, that would be different for each tech.
Personally, I assign all help desk tickets to tech. That takes all tickets from 'Open' to 'Assigned'.
I than encourage all techs to communicate via Notes to Clients, to get Clients use to this process, and encourage Clients to respond to the ticket (instead of a separate email).
IF a ticket needs to be done in the future, set the Status to 'Scheduled'.
Also, subscribe your WHD calendar to your "used" calendar (we use Google, so I have my tickets synced to my Google Calendar).
When we are done with tickets, we set the ticket status to "Resolved", which allows the client 48 hours to take the ticket out of "Resolved" state and put it back into "Assigned" state if they reply.
If we complete the ticket 'on site' where the client agrees the ticket was solved, our Techs immediately "Close" the ticket.