Ask to see the contractor's "pocket license" or Home Improvement Sales (HIS) registration. All contractors are issued pocket licenses which show the type of trade for which they are licensed and the expiration date of the license. Also, effective July 1, 2000, all contractors involved in the business of home improvement must be a Certified Home Improvement Contra tor. Ask to see some additional form of identification so you know who you are dealing with. If the person says he or she is representing a contractor, but can't show you a contractor's license or HIS registration, then call the contractor and find out if the person you are dealing with is authorized to act on behalf of the contractor.