A contact center dialing a telephone number to a destination party, such as a debtor, may discover that the number is obsolete, e.g., the number has been reassigned to a new subscriber. A purportedly current number (called a ‘skip-trace’ number) may be obtained for the debtor, which may be a wireless number. Until the wireless skip-trace number has been confirmed as being associated with the debtor, an agent manually dials that number to minimize liability to the contact center. Once the agent has verbally confirmed the skip-trace number is associated with the debtor, a record for this number in a dialing list is updated allowing future dialing attempts to occur automatically, by using a predictive dialer. In one embodiment, a dialing list module processes the dialing list so as to detect when a number is obsolete and update the corresponding record when the number is confirmed.