<p>I just found out that Cornell has only received one of my teacher recommendations! If I get my teachers to resend their recommendations ASAP, would it be ok? How will this affect my chances?</p>
<p>If Cornell viewed the extra recommendation as crucial to your application, they would have asked you for it after they realized they only had one. The recommendation probably isn't going to make or break your application, but if you think otherwise, you have nothing to lose by resending it.</p>