Abstract: An apparatus and method for converting a first user interface used for existing applications running on a host computer to a second user interface for use on a client computer. The apparatus intercepts prompts and request for input from the host, converts them to a form appropriate for use on the client computer, and passes the converted prompts and requests to the client. The apparatus can store information for use at a later prompt or request, branch on the stored value to vary path execution, and handle errors generated by incorrect input.