Hi there! I'm Vanessa, designer and drafter. I will like to offer my CAD services to help you modifying your drawings. First of all, I will like to see the drawings and the list of the changes you want to make. Once I see those items, I can tell you if I need more info, such as dimensions (as you said), etc. So please, feel free to contact me to discuss more about it.
Have a nice day!