Hi Max, well you can select your pentagon surface and use ShrinkTrimmedSrf (http://moi3d.com/3.0/docs/moi_command_reference10.htm#shrinktrimmedsrf) which will snug down the underlying surface's control points to hug the active trim boundary so the points are closer to the border.

But you can't have a 5 sided underlying surface itself - it's a fundamental thing to NURBS object structure that the underlying surface has a quad structure with control points arranged in a net of rows and columns.

- Michael