HRHD - Send email when user responds SR

Content

Hello experts

Does anyone know, how could i send an email, in HELP DESK, after the user responds something in the ticket (Service Request).
Example:
User 1 creates HR SR -> Agent responds -> User1 Gives more info (responds) -> Agent receives email
Would be nice for it to change status from waiting to in progress as well.

Can it be done?
Which trigger should i use to make it in Object Workflow

Thanks a lot

Version

20D