Well, I don't know if there's a better way, but I exported the topos to a (3D) DWG file, imported the DWG file back into a new project, created a topo from the dwg, then copied the new topo back into my project.

It actually worked quite well, all the topo points seem to follow how I originally placed them, but there's got to be an easier way?

EDIT: Well (part 2), I just noticed that "Merge Surfaces" tool... doh! I had no idea you could use that to merge separate topos... don't know when that tool appeared or maybe I just never had reason to use it before. At least I can blame this all on the holiday weekend...

Well not Quite

EDIT: Well (part 2), I just noticed that "Merge Surfaces" tool... doh! I had no idea you could use that to merge separate topos... don't know when that tool appeared or maybe I just never had reason to use it before. At least I can blame this all on the holiday weekend... [/QUOTE]

If you do a bit of testing you will see that the Merge surfaces button does not actually merger all the points from both surfaces into one surface.
I only write this reply so others reading the post are not mislead.

I have found a nice trick is you still use the create from instance tool while editing an existing topo.
so you can edit the new topo you have edit and then create from instance, pick the original survey and it will add all those point in.

I often use this tool when I get an updated survey.
I make a new version of the survay that only has the contours from the new updated parts.
then I link it in and edit my existing topo.
delete all the point in the updated area.
then I just import from instance from that new file.


I know that is messy, but it's the best I have right now.