Situation: I have booked a ticket with KLM that combines a flight to Schiphol with a Thalys train to Brussels. The transfer time at Schiphol is 1 hour and 43 minutes and it was not possible to book with a shorter transfer time. It seems likely that I will be able to make it to the Thalys train departing one hour earlier, which would increase my chances of being in time for a meeting in Brussels.
Question: Would I be allowed to board the earlier Thalys train on my KLM ticket? If not, is there any way I could make this possible, for instance by paying an additional fee?
Additional info: I read in this forum thread that it is possible to take an earlier Thalys train if you have some kind of Flex-ticket, but I don't know if my KLM ticket would count as a Flex-ticket or if I could somehow make it a Flex-ticket.
(This previous question is about skipping the train leg in a similar situation. I don't want to skip the train leg. I just want to take an earlier train.)