If you modify your part that the drawing refers to it will update the drawing automatically. If you have used show dimensions rather than created new ones you can do this from the drawing. If you want to create a completely new part that is similar to the first you can copy the part and if you have your config.pro set up properly it will copy the drawing with the part, giving it a new name also. I don't have my copy of Pro/E in front of me so I can't give you the exact option off the top of my head, but please email me at the adress below if you can't find the option.
Hope this helps.
Kellie
Kellie@141.com