Hi Niharika

I'm assuming you are using SSRS when you say a report filter parameter?

My MDX isn't great but what I'd do is create set using a range. So using you example instead of the SUBSET I'd have something like this:

{[Date DIM].[ISO Week Short FI].[1] : STRTOMEMBER(@Date).PrevMember} ON ROWS

Where your date parameter would have the form of a member (e.g. "[Date DIM].[ISO Week Short FI].[19]").

Hope this works for you.