direct change

[EDU]

Good morning. I'm new to work, so if I shoot some shit, forgive me.
I have a part created with sforms, emptying thickness 2.5 mm, and a series of manipulations. I should change the part so I have it as on the photo. going to the tree, and trying to change the individual operations, I find that all the rest that follows no longer has references, and everything and to remake. Please give me a clue, from where I could start, the path to follow (for lack of experience my brain cannot generate a process

 

[freexf]

the direct modification should be made with the flexible modeling module that is not so close by being at first arms.
Otherly you have to climb a little higher in the building tree at a certain level of feature that you had to make the modification of a specific feature or add others.

 

[EDU]

Thank you very much