Surface Edit Tools

Surface Edit Tools menu commands include items the below.

Untrim Untrim a surface.
Detach Loop Detach trimming curves from a face.
Split at Isocurve Split a surface at isocurves.
Shrink Trimmed Surface Shrink the base surface of a face to be as small as possible.
Smooth Smooth a NURBS surface.
Negate Negate a surface.
Insert Knots Insert knots to a surface.
Remove Knots Remove knots to a surface.