Yes.  If your COI course status in CITI is "Completed/Not Passed", then you can go back into your COI course and retake one or more quizzes in order to get credit for the course.  Note that all quiz questions must be completed correctly to get credit for the course.  CITI has provided a new FAQ that describes how complete these steps. 

After you've successfully completed the course, you'll get a certification email from CITI within 24 hours.