From what I've understood, you should follow these steps;
First, you may use "Export to LandXML" (in Output ribbon) on another drawing in order to export the surfaces you've already labeled and then land them(by using command LANDXMLIN) onto the drawing where your new surfaces that are going to be labeled exist.
So that, you've got all the surfaces in the same drawing, both labeled and non-labeled ones.
Secondly, you should delete all the data that the surfaces you've already labeled have this way:
Surface Properties > Definition tab > Right click on each operation type and select "Remove from Definition" and rebuild the surface.
Then, you go into Toolspace > Surfaces > Expand the labeled surface (the surface you just removed its data) > Expand Definition > Right click on Edits > Select "Paste Surface" and select the new surface you want to label.
The labels must be associated with the new surface now.
Kind regards.
Erdem Çelenk
Civil Engineer
Unless I'm missing something, in newer versions of Civil3D you can simply select the AECC_SURFACE_ELEVATION_LABEL objects and use the PROPS dialog to change the referenced surface.
Hello Terry,
You are totally right, yet as you know, if you have a great number of surfaces and if these surfaces seem like engaged(like one on the top of the other), it won't be easy to understand a label's referenced surface and you will have to select each one by one in order to see its referenced surface.
Erdem Çelenk
Civil Engineer