>I would like to replace the expression builder that appears when a user is adding a field to a report. Setting the _GetExpr to my replacement expression builder will work in that my builder shows up. However, regardless of what I return from my builder, it is not put into the Report Expression. Has anyone managed to do this sucessfully ?

Is your replacement VFP code? If so, you don't have to use _GetExpr and GetExpr(), you can just call the code. If not, what is it? Can it be defined using DECLARE Function IN Library, then called? Just looking for another way to get to your "replacement" other than calling GetExpr().

HTH,