How to delete splines but retain control points?

[Tom]

Hello Hashers-

I was trying to do something which I thought would be simple but I ran into a problem. The attached jpg shows the situation.

I have half a sphere and I want to delete all the splines and just keep the control points in place while retaining the half sphere shape. I can delete all the splines horizontally and the control points are intact. However when I select the vertical splines EVERYTHING disappears when those splines are deleted.

 

My method is I select the spline by clicking on it. I use the comma key to select the entire spline and then I use the "DELETE" key to get rid of it. One of the suggestions online was use "Shift +  D" key but that didn't work.

Does anyone know how to retain the shape of an object using control points while deleting all the splines?

 

Many thanks,

Tom