Yes You Can! All you have to do is
1. Login to the Event site on https://eventregistration.ctnadmin.com/
2. Click Events on the header. There you can see the list of your events.
And click on the My orders from the Events
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Then you can see the tickets there. Click on the click here link under the Upgrade corresponding to the ticket that you want to upgrade.
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From the next page you can upgrade your tickets by purchase the new ticket .You need to purchase the ticket of amount greater than the existing ticket amount.
