Question about score sending

<p>I just took the June SAT and CB says that I can submit my score to 4 schools for free before June 10. If I take the October SAT and get higher score, can I resend my score to the 4 schools to which I send my June SAT score?
Also do you think that a score of ~ 2150 is enough for any of the competitive schools? I'll leave the top ones to October, I guess.</p>