It seems that business or first award space to EZE doesn't open until a week or two before departure. Can I book 2 economy award tickets ( hope the business/first seats open later) and call to upgrade to those awards without fees - just using more miles? We want 2 business/first tickets from WAS to BUE for next December and I can't find anything this far out with AA miles. Any other airlines I should be looking at too? Thanks!