I recently did something similar by allowing the user to change the view from a weekly basis to a period basis.
1) Create a Parameter (for example called Date Filter) with Data type as "String" , then enter value options as "Transaction Date" and "Program Date"
2) Create a Calculated field using the parameter:
CASE [Date Filter]
when "Transaction Date" then [Trans Date]
when "Program Date" then [Program Date]
Add the parameter control to your worksheet and put the calculated field on the column or row where you normally would put either trans date or program date.
The user can then select either Transaction date or Program Date and the date field on the graph will change accordingly.
Hope that helps!
Thank you. It worked perfectly!