I find it easy to create an offset section, but if you create a full section first, it is not obvious how to change the section type and not have to recreate the view.
Right-click on the section line and select Edit.
Using the Line command, draw lines that represent how you want the offset section to look (make sure the lines touch each other).
Trim the original line so you have one start point and one end point.
Finish the sketch. Notice how the section cut updates.
Note: This Inventor tip has not been reviewed by a Cadalyst tip reviewer.