What happens when an agent replies to an email notification from their agent email address?

Whenever an agent replies to the thread of an already existing ticket from their mailbox, it will be added as a public note on the ticket.

If the agent sends an email to the support email address as a new thread, it will create a new ticket with the agent as the requestor. 

To append a new email to an existing ticket, include the Ticket ID at the beginning of the Subject line of the ticket in the format, [#{{ticket.id}}].

For example, add [#1234] at the start of the subject of a new email to append that email to Ticket number 1234.