Marketo Integration

If we set up the zoom/marketo integration past webinar registration can we still push the entire list of registrants and attendees to marketo?

We have already successfully set this up to integrate and communicate with Marketo. However, we did that after people had already been registered to the webinar. So, is it possible for you to basically say that those who are already registered - JUST registered and change the timeframe to today, so that Marketo can view it and it will sync with everyone who is currently registered?

This is an urgent matter. We look forward to your help. Thank you!