Hi Kimberly -
What you could do is setup a smart campaign for all Leads needing this change to happen on the record. I would recommend something like the following:
![0EM50000000STNe.jpg 0EM50000000STNe.jpg](/t5/image/serverpage/image-id/619iA5605E99868A4A9C/image-size/large?v=v2&px=999)
Before doing this, you will need to go into the admin panel, and the Field Management screen to ensure that all boxes are unchecked for Email Address
![0EM50000000STNj.jpg 0EM50000000STNj.jpg](/t5/image/serverpage/image-id/621iC5A18BB83C4E3C41/image-size/large?v=v2&px=999)
After your change is done, I would recommend going back into the Admin panel and re-checking anything that was checked prior.