We are currently booked on a 5 day Destiny and want to change to a 7 day Splendor within the same week. Will there be a penalty?
If outside of penalty no. If inside of penalty it can depend on several variables. One of them being how far you are inside of the penalty period, and a $50 service fee would apply at the minimum.
I just wanted to add that now that there are Early Saver Rates out there.... there are different penalty rules for those.
That is a very good point. Those rules are quite different. tim c mentioned about the $50 per person fee as well that applies to changes with Early Saver rates.