Johnathan Wright

Perhaps I'm missing something here but it would seem to me that the problem has nothing to do with what the customer is saying in their 'Thank You' response.  Rather the issue is that Zendesk allows an email into the system to change the status of the ticket.

Why not simply change the logic so that:

IF Ticket = "Closed" 

Subsequent emails ARE written to the ticket BUT status is not changed.  The email will still be in the ticket, it will still get sent to the agent and any persons CC'd on the ticket but a simple email sent to a closed ticket cannot change the status of that ticket.  If the user has said Thank You, but I need more assistance, then the agent assigned to that closed ticket is the only one who can open it back up.

That should not be hard to do at all.