In the mass email panel you can now resend specific emails. Here is what it looks like in the Recipients section when you click on the details of the mail now.
The new "Send Again" button appears on the left and it pops up a box - from the box you can send the email and EVEN update the person's email address before you send it.
So, a usage model like this example, the agent Linda has a bounced mass mail. We click on Send Again and we update her email to be correct.
Here's the best part; it updates Linda's contact record as well so it heals the real data (the person's data record: client, agent, insurance agent, etc).