How to delete a topo subregion???

[christo4robin]

How can I delete a subregion without losing the topo information in it? I tried just deleting the subregion, but then I don't have topo lines where it used to be. Also, I tried editing the subregion sketch and erasing the lines and finishing sketch, but, same result. Merge surface seems to be only for surfaces that have been split. I checked help, but only found the create subregion information.

Any insights?

[Nevine]

I don't know if there is a better/easier or cleverer way to do this, but I end up making sure I have a 2d detail lines, or a linked 2d revit drawing or autocad imported drawing of the site and I trace my topo over it by selecting the lines, that way when I have to revise subregions which I do by merging them back with the main site and redrawing them, I have a base to redraw from. I read at one point that you should take the topo and put it on in an existing phase before working on it, but I think this is for grading.