change field in report

I have a field in a report that I want to append or not append a string to it depending on an option in the form that calls the report.

Right now, it calculates the month using "format" depending on what month and year are chosen from the previous form in combo boxes.

There are also 2 options on that form and if the user chooses the first, the code above works fine. But if the user chooses the second, I need to append " And Previous" to the field.

Is there a way to do this? Otherwise, I guess I'll just have to create two reports... one with it and one without it and launch the report based on which option the user picks.

Anybody?

Build a function that will handle this field.