Yes, you are able to resend the reference request, if a reference has not replied to your original request. If you would like to resend, click on the application for which this situation applies, click on the reference that you would like to resend the form to, and click "Resend" located at the bottom of the page.
See Also:
Who does AmeriCorps consider a valid reference?
How many references do I need?
How many references can I enter?
What happens if I have more than two references?
How do I know if my reference responded?
Can I change my references once I have submitted the application?