Convert Rich text field to normal text

Hi community,

Do you know of any way of converting a field from rich text to normal text?

The oposite is possible: change a field from normal text to rich text but the opposite seems not to be true.

I have a customer that allready has data in a rich text field that stores email addresses and I need to use that email into a business process, 

but the email business process element does not read rich text (but it reads normal text)

Thanks,

Luis