My wife and I are planning a trip from Denver to Maui in May and have a coach reservation using Chase Ultimate Rewards points to Korean at 25k/passenger RT flying on Delta metal. I want to book us in First Class for 45k/passenger but there has not been availability when I have reached out to Korean Air by phone or email. Is there a way to track to see if availability opens up? I'm not an Expert Flyer guru but am curious if there is a way to do it through that or another tool.