Dickinson orders one thousand widgets at $5 per widget from International Widget to be delivered within sixty days. After the contract is consummated and signed, Dickinson orally requests that...

Dickinson orders one thousand widgets at $5 per widget from International Widget to be delivered within sixty days. After the contract is consummated and signed, Dickinson orally requests that International deliver the widgets within thirty days rather than sixty days. International agrees. Is the contractual modification binding? Why or why not?