Eternal bonding ceremony set - but can I upgrade?

[Impish]

I did a search for this and can't find anyone that had this inquiry. My boyfriend and I have our ceremony reservation set for 6pm (in roughly 2 hours). This is the free standard plan. We've gone thru and done the quest up until this point and we're now wondering if we can upgrade to the next tier and keep our reservation spot for the ceremony. Or, do we have to do the entire quest line again and make a new reservation? Thank you for your help. Seriously, this has been the most helpful game community we've ever played on.