no.
it's called a termination letter
NAFTA’s Article 2205 states: “A party may withdraw from this agreement six months after it provides written notice of withdrawal to the other parties. If a party withdraws, the agreement shall remain in force for the remaining parties.”
You know what? I was wrong about that, and I stand corrected.
That being said, the incentive for Mexico and Canada to negotiate separate trade deals with the US is low. They could enter into a deal with each other to which we might be subject to agreeing to in order to supplant NAFTA. Canada and Mexico are besties.