Add relative dates to Export filename

I have a scheduled job that gets sent out on a weekly basis. It covers the Total Sales for the entire week leading up to that day. I would like the Export filename to show the date of the Monday BEFORE the report is sent out. So, if the report is set to send out every Friday, the date listed on the report should be %m%d%y, strtotime(4 days ago); or something of the sort. The date printed on the file export needs to be the date that STARTS the week.

Is there a way you know of that I can accomplish this?

Thank you!

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