Hi nordzway, it's helpful if you would also post the 3DM model file with your curves in them instead of only a screenshot. With the 3DM file it's much easier to test different things and give better advice.

But from what I can tell in your screenshot you would use the Construct > Sweep command to do that. But it looks like you're only selecting a single profile curve for your sweep. Instead of selecting just one profile curve you would need to select both the starting and the ending profile before doing the sweep.

You can give Sweep multiple profile curves to control the shape at each station, it's not limited to only one profile curve.

- Michael