Hi.
Situation 1: If your application is at your local CHC, then you can go to the cic website from where you can send a case-specific enquiry (which I am sure you know now). As you know, there is a separate link to each visa office in order to prepare a case-specific enquiry. You've already prepared your modified job description. Now you can prepare a letter explaining changes made to both the description and NOC. Submit all those simply by attaching them to your mail. But I think signing the documents, putting dates in them, and then having them scanned would be better.
Situation 2: But if your file is still at CIO, then your best option is to send them hardcopies of the above. Please make sure you write your file number in the Sender Address section on the envelope provided by your Courier Service company and highlight it with a bright marker, before handing it over to the Courier guy.
My case falls in situation 2. That's what I have done.
mcgyver