Comm100 Ticket supports multiple enabled email accounts. When you respond to tickets, the Default Email Account is used as the default From email address.
Log into your Comm100 Control Panel.
Go to the Ticket portal, and click Email Accounts.
Select one email account from the drop down list under the Default Email Account and then click Set as Default.
Now you have successfully set the default email account for your ticket reply. You can check it in your agent console. If want to add more email accounts, read this article to learn more.