Actually, I would not do it this way only because it seems like a lot of hoops to do something quite simple.
I would set up the query with the proper fields that I want to come out of it, including UpdatedBy, without any criteria. The make the query the record source for the report. If you open the report by itself, it would give you all the records. However, if you open the report via the form, the code would look like this.
DoCmd.OpenReport stDocName, acPreview, , "[UpdatedBy] = '" & Me.cboStaff & "'"
Michigan Dept. of Environmental Quality
Air Quality Division