StoreRocket's store locator has a built-in feature that whenever the user's search doesn't provide any nearby results, it shows a collect lead form that allows the user to be notified about new locations in the future.

When a user submits the form, the new lead will be saved on this page.

You can export the leads and it's up to your preference on how you wish to notify the user in the future (you can add their email to a newsletter or to a CRM for example).

This page has the Leads Form settings.

You may also edit the text in the form on the Languages page.