dynamic variant for program RBDMANI2

Hi All,

How do we create a dynamic variant for program RBDMANI2which is a background job.

For the below variant I want to create a dynamic Date range with one month.

If it is executed on 08/15/2013, it should take date range as 07/15/2013 to 08/15/2013 without changing the other inputs.

If it is executed on 08/20/2013, it should take date range as 07/20/2013 to 08/20/2013. i.e. for one month.

How to acheive this? Please help.

Thanks,

Haritha