You can use Contact-Free Prize Fulfillment to contact winners and collect a new / updated W-9 when necessary.   To get started, go to Front Desk > Listener Database > Listeners When you've arrived, look-up the winner you wish to contact.
Next, go to "Listener History" the click on the the "distribution date" for the contest you wish to contact the winner about.
To have the winner confirm/update their contact and personal information prior to signing their W-9, click "Email Listener for Info." -or- If you are confident the winner info is accurate, (maybe this is a previous winner), click "Collect W-9" to simply request signature on the W-9, and bypass the need to ask the winner to verify/provide information.
Assuming you need to have the winner verify/provide their information, you will have clicked "Email Listener Info" and see the resulting pop-up message. Here you decide which forms to send (the W-9, the Winner Release Form, both) and can also customize the message sent to the winner.  Subject and Email Body are both editable. When ready, click "send" to email the winner.

When the winner has updated their information you will receive an email saying - at which point you may proceed to Front Desk > Listener Database > Utilities > Process Winner Signatures to process (create and save) the winner's signature on their W-9.