4GL Help

Hello all, I'm desperately searching for a function in 4GL that allows me to search for a string within a variable. What I need to do is take a string created by a consruct and replace part of it with a different string for example: If varWC is the clause created by the costruct, 1) search for date1 = <date> 2) If date1 exists and date2 exists then replace both with ''. 3) Tack on the back of varWC new date clause. TIA, Howard sending to informix-list