Hi Tony, you'll need to set up a keyboard shortcut with the command ShrinkTrimmedSrf on it, then use that keyboard shortcut for activating the command.

> The control points do I need to change the curvature of the middle surface and leave unchanged
> the curvature of the original surface and then make a connection between the two.

You'll probably want to use the Construct > Blend command for doing this, it's usually best if you cut away a zone of open area between the 2 pieces, something like this:









If you run into a problem with Blend, make sure you have edges selected, not just curves selected. If you have curves overlapping on the same spot as edges you have to hide or delete those curves so you can select the edges instead.


> How do you activate the command to toggle the edges concatenated.

Do you mean to join the pieces together at the end? That's the Edit > Join command.

- Michael