If you have the Marriott confirmation number and it has been at least an overnight since you received the II confirmation, you can look this up online at Marriott.com. The Marriott confirmation number is the 8 digit number that is on the II confirmation certificate, it usually begins with 8, though it could be 9.
Log on to your Marriott.com account and go to Change/Cancel Reservations. There will be a place where you enter your last name and the confirmation number. Once the reservations comes up, you can view the room details. There should also be a link to e-mail the reservation.
If you call 1-800-MARRIOTT, you can even have them add your Marriott rewards number to the reservation so it will show up in your list of reservation in the Change/Cancel Reservations section of your account.
Edited to Add: It doesn't look like you have to enter your name now to search a confirmation, just the confirmation number. If it hasn't been 24 hours yet from your exchange confirmation. Log in to II and look at your "My History" to get the four or five character Unit Code for the Ko'Olina unit you exchanged in to. Post that code here and someone will know what it is.