Prerequisites
To use a selection variable for date calculation, you must have defined a date field as a parameter or select-option in your program.
PARAMETERS DATE LIKE SY-DATUM.
Procedure
To assign a date calculation variable to an existing variant:
Add further parameters if necessary. To subtract days, the minus sign must follow the number (for example, 10-).
Note that you cannot change the proposals in the list or add new proposals.
Result
You have assigned a variable to a variant for date calculation. Note that after choosing the selection variable, you must save the attributes again on the attributes screen.
Use the selection options pushbutton on the selection variable screen to enter further options for the date variable.