Change mesh shape without losing faces

Hi!

I am trying to change meshes’s shapes in this way (increasing the low part):

I am using a script to do it, but some of the faces are lost in the proccess. I tried with the command mesh.FillHoles() in the script but it doesn’t fill it right.

Can anyone help me?

Thanx!

snippet.3dm (5.9 MB)
snippet.gh (8.5 KB)