During periods of high volume and extended wait times, the Queue Callback application allows Evolve IP call center customers to offer end users the ability to request a callback, based on pre-determined call center conditions, rather than having to wait in queue for an agent to become available. The Queue Callback application allows customers to configure thresholds for when the callback option(s) will be presented to their end users. Call center customers can purchase concurrent call licenses in bundles for offering queue callback to their end users.