What a beautiful amazon you've got there!!!!
torrap, be persistent and consistent when changing food!!!! I've typed this out numerous times already as it should be somewhere and everywhere on the forum...lol....but here I go again....
Here's how I do it, a bowl of pellets all day, any pellets you want to use to start. Any pellet is better then no pellet! Then in the morning I feed fresh fruit & veggies, in the evening I feed a table spoon of seeds. Then next day toss the left over seeds/crumbs and repeat the process. During this process, IF you see him eating pellets, stop feeding seeds period, not even that night. Don't give any treats or nuts or seeds! I would skip all that for a month or so before offering them in small amounts like few pieces or few nuts...