Yes, when a Call or Action Alert is Archived, it can be restored.
  1. Navigate to Advocacy > Call Alerts (or Action Alerts, whatever the case may be)
  2. Scroll to the very bottom of the page and mark the checkbox "Display archived alerts"
  3. Scroll back to the top of the page and enter the name of the Alert in the search field
  4. Click the Search button
  5. Under the Actions column, click the Restore link