Quoting what you "dig up" on the internet is just as bad as people posting wrong days like the 6 days etc.. if Royal is not following that. That is also the final manifest after passengers have to be checked in. I believe that they also must submit a preliminary manifest, nonetheless, they close their sailings for bookings around the 24 hour mark (plus minus a couple hours. It can also be closed earlier of there are no cabins available which is why I never tell anyone that needs to make changes to the 24 hour mark. Best to go with 48 to 72 to be safe.