Menustrip item disabling

Question

I have three form,one is Admin , one is Employee and another is Mainform and this mainform contains menustrip bar with some item.Admin and Employee form has a button "ok".

Now i want when i click button " ok " in Admin form and the Mainform comes and i can see all the item in menustrip bar but when i click button " ok " in Employee form that time in mainform menustrip bar "EDIT" item will be as disabled.

Can i do it?
What is the code?
I don't know the code.