Use Draft in Flange mode or Multi-surface draft to create a surface from a set of surface curves, at an angle relative to the original surface.
Pull surfaces from curves of an existing surface
Pull a single surface from tangent-continuous curves of existing surfaces
As each curve is added, it is highlighted in yellow, and a flange surface is built. A single flange surface is created no matter how many surface curves have been selected.
Set the angle or height at a point along the surface