If your just trying to make a harder edge some where on your model. Like a crease in it thin what mike said is the way to go.
If you the outside edge of a poly object that your trying to get out farther..
well you could use the extrude edge. that will make another edge and you can pull it to where you want.. poly faces will come in-between. since you can't have just a edge with out a poly . this would be the way to go..
I think I'm understanding what your after now. Thanks for clearing that up.. I think one of the 2 responses will help.
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