Question about upgrades
 

I'm looking at a couple of flights BKK-AMS in late April/early May. I do not usually fly KLM, so I'm not familiar with their site or tools but have a lot of Chase miles. I did a check and found that on one date in May, upgrades are available for 21,000. The dates I checked in April were 74,000.

Is there a way for me to see a calendar of dates for upgrades so I can try and book on a 21k day? There did not seem to be a way to look at multiple dates or even try another date without starting the entire search over.

Also, what would the odds of a paid upgrade be for this route? Is BKK-AMS usually busy?

Thank you!

I would imagine that the upgrade price in miles is more dependent on the booking sub-class than the actual date (although one influences the other). Was the price for the economy flight requiring 74,000 significantly cheaper than the one requiring 21,000? If so then you can get an idea of the miles required by looking at the ticket price on various days.

BKK-AMS is always busy, in Y and in J - ticket prices are often relatively low resulting in fuller planes.

Call the KLM service line and ask, that's by way the only reliable way to check if there's upgrade space available.