You could, but then there would be a delay in your order's production! (There is also a $27.00 fee for our designers to handle your files).
The best way to handle this is to log into My Account and click on the link to Complete your project or Approve/Reject your proofs.
When you reject a proof with new files, you'll be able to upload them immediately after.
See also - https://support.duplication.cdbaby.com/hc/en-us/articles/205395858-How-do-I-approve-or-reject-my-proofs-