Several websites have articles about Riviera and Marina having a complete refit. For example:
https://www.cruisehive.com/two-luxury-cruise-ships-to-undergo-complete-transformation/69787
It says Riviera is having hers done right now and I understand she is in dry dock now. But the articles say Marina is scheduled for October/November 2023. However, the Oceania website still show cruises running that time next year. In fact, it has full availability in all cabins including the