How to change the subject in an email in Gmail

Sometime early this year Google changed the format of gmail.  One used to be able to see the subject of emails at all times, which made it easy to change the subject when forwarding or replying to emails.  The new gmail format is more compact, but the ability to change the subject is still available.

Here is how to change it when replying:

 

 A box will open, and one of the choices will be Edit Subject.  This will open up a new email where you can change the subject.

 

 This is where you would click to change the subject when forwarding an email.