A more finished look is made by installing a return on the end of each molding. That creates a corner by making an end piece of the molding which is installed on the end of the molding.

Here is a link that might be useful: Crown molding return

The proper way is to cut a miter for an outside corner, with the long point being the length to where you want the moulding to end (about 1/8 short of the end of the wall), then cut other piece just like you would do if turning the corner. This piece is now cut just long enough to return to the wall. It is referred to in the trade as returning a piece on itself, and is how to end all profiled material in this situation.

Is this what you mean?

Here is a link that might be useful: crown molding return