Errors on submitted visa applications

We are based in Toronto, Ontario, Canada and submitted our visa applications online via the CVASC website, but realized after submitting that there were a couple of errors (passport number, validity length of visa). What is the process for us now? Do we

1) Submit an entirely new application?
2) Is there a way to revise / correct the information on the applications once submitted?
3) Make an appointment and revise the information on-site with the visa officer?

Really appreciate any help. We have called the CVASC, but it just rings several times and then disconnects.

Thanks.