I'm not quite sure if this is what you are looking for but...
' Open the report in design View
DoCmd.OpenReport "test", acViewDesign
' Set your margins (default is pixels where 1" = 1440
' Pixels
Access.Reports("test").Printer.LeftMargin = 770
Access.Reports("test").Printer.TopMargin = 1440
Access.Reports("test").Printer.RightMargin = 770
Access.Reports("test").Printer.BottomMargin = 1440
' Open the report in NormalView
DoCmd.OpenReport "test", acViewNormal
' Close the report
DoCmd.Close
Note that if your controls are places outside these "new margins" they will "truncate" when you print.
Hope this helps.
Lt