possible to use passed params with variable?

I am trying to make a copy of an existing report. The users want to receive this version as a weekly.

Currently, the report is on demand with 'from' and 'to' dates. The problem, is that there is a subreport as well. that is also getting these passed dates.

What I want to do is run this report every monday am for the past 8 days (they want Sat to Sunday data).

I would like to keep the params if that is possible. Otherwise I am not so sure how to pass dates to the sub report.

also on the scheduler would I be able to schedule for the past 8 days.

If not I will have to see how to pass variable dates rather than param dates.