Webreporting: Variable offsets

Hi all,

i have created a query with a time variable for the characteristic "calendar day"! I am using a range within an sap exit variable "actual calendar month"!

To get this i restricted a key figure by selecting "range" and use this variable in restriction and offsets. The from offset is "0" and the to offset is "-7" to see the last 7 days. How can i change this offset with command url in web so the user can deside how many days he want the key figure to be restricted??

Regards,

M. Erbil