Thank you for your quick response! What is the My table you are referring to? After I do this expression, then I need to take the PlanEndOfMonthDate and add 15 months for a final recon date. Final Recon Date: DateAdd("m",15,[MonthEnd]). However, it doesn't always give me the correct date. For example. PlanEndOfMonthDate is 2/29/08, the final recon date is coming out as 5/29/09 but I need it to be the end of May, 5/31/09. Any suggestions how to correct my calculation? thanks Michael!

I tried the following PlanEndOfMonthDate: DateAdd([mm],DateDiff([mm],-1,[PlanEndDate]),-1) and a box comes up for me to enter the month parameter value for mm. How do I get the code to look at the month in the PlanEndDate so parmameter value box is not listed?