Edit the Reply template

Edit the Reply template

I have been looking all over and trying to figure out how to edit the reply temple to the customer. I ask because we need to edit the Subject line to match the email they receive after their initial contact. --

ie the Subject will say
[XM #100] Your ticket has been created

However after an agent replies the subject is changed to
Re:[## 100 ##] Subject of the ticket

We want to edit the reply to match the initial ticket they received.
Re:[XM #100] Subject of the ticket

Is this possible?