How can I change the default shipping comment on Dawn product page?

I’m using the latest version of Dawn. The products page has a default comment that shipping is calculated at checkout (see image below). I offer free shipping and would like to edit this comment to simply replace “calculated at checkout” to “free”. can anyone help me?

Dawn 10.0 changed the Action Options a bit. Edit Language has been replaced by Edit Default Theme Content. Your guidance helped me find and alter the Product Page shipping information that was giving me problems. Thank you.