Using assigned value from a dropdown list to populate a field

Using assigned value from a dropdown list to populate a field

Hello, 
I use a dropdown with a global list that has assigned values. The value is a name, the assigned value is the corresponding email. 
When selecting my name from the drop down, I want the "Save for later" template to use the assigned email as recipient. 
Alternatively, I'd like it to populate an email field - hidden - that I would use for the Save for later recipient. 
Nothing I have tried so far seems to work, I wonder what the use for assigned values is?

Thanks for any tips