We used to use Spiceworks for our I.T. ticketing system and one of the things we liked about it was the ability to email the ticket with commands in the body of the email to do certain tasks. For example we could reply to a ticket via email with the command "#close" and it would close the ticket. We've reproduced some of this functionality with automations using the "update record" actions. We're able to close tickets and assign tickets to our selves if we use keywords in an email reply to the ticket.
A functionality we haven't been able to reproduce is an email reply that can change the requestor. In Spiceworks we would use this with emails a user would send directly to one of us in the IT department instead of going through the ticketing system like they're supposed to. We would just forward the ticket to the ticketing system with a command "#created by <email address>". The Update Record action does not list "requestor" as one of the choices that can be updated on an incident via automations.