This paper proposes a method, called RLR (RSVP library redirection), which can transform legacy Internet applications into RSVP-aware applications without modifying their source files. RLR achieves the transparent transformation by redirecting procedure calls from the socket library to the RAPI (RSVP application programming interface) library. For UNIX operating systems, such as Linux, Free-BSD etc., the redirection can be realized since the related mechanisms of procedure call interception are supported in these operating systems. In addition to the advantage of transparent transformation, RLR can allow a single RLR software module to be used for multiple programs if they have similar behavior. We have used one RLR module to transform several FTP applications to be RSVP-aware. The experimental results show the feasibility of RLR.