If there are passholder seats still available on the train you can make a reservation through the link below.

There is a limited number of pass holder seats on Thalys. On popular departures and during high season, those sell out weeks, and sometimes months in advance.

The best place to see the availability of passholder seats and make reservations on Thalys is 

https://www.b-europe.com/EN/Booking/Pass#TravelWish

If you don't get any result, press "later trains" and eventually you will find the next available connection. 

If you have a mobile pass you need to generate a Pass Cover Number in order to make the reservation at b-europe. You do that here in the PCN generator:

https://community.eurail.com/news-and-announcements-39/pass-cover-number-generator-is-live-5653

The next Thaly train from Paris to Amsterdam with passholder seats available is on Tuesday afternoon, so you need to find other trains to travel with if you want to reach Amsterdam tomorrow. . Maybe the TGV to Lille and IC train from there.

There are no pass holder seats available anymore on Paris-Amsterdam tomorrow.

There is still availability on Paris-Brussels in some trains. Not in the train leaving at 6:13, but e.g. 7:25 and 7:55. From Brussels, you can use the reservation-free intercity train to Amsterdam. It runs every hour, e.g. at 7:44, 8:45, 9:45 etc.