How did Kennedy administration respond to two letters from Kremlin in movie Thirteen days?

Realizing that the situation was no-win situation due to the destruction that would happen if they fired the missiles, Khruschev sent a letter to Kennedy saying that they will remove their missiles from Cuba if the U. S. swears not to attack it. They also sent another letter saying it will dismantle the missiles at Cuba if they remove their missiles at Turkey. Though the Americans replied to the first letter, they ignored the second. They said Robert Kennedy to negotiate with the Russian ambassador Anatoly Dobrynin where they secretly removed their missiles in Turkey and the crisis ended.