This is how a stair displays......
Therefore the only way to achieve this in Revit is to use a combination of the linework tool, a mask region and then add a break line were you want the break to display on plan.
If you take a look at this image below, you will see that a combination of a mask region, invisible lines and hidden lines have been added to display the ramp as we require. It’s also worth using a reference line in section to work out where you want the cut to display in plan, based on the cut plan for the plan view.
This is the resulting ramp in all its glory with added linework and mask region.