I acknowledge that [specific action or situation] occurred. However, I respectfully submit that there were extenuating circumstances that contributed to this situation, which I had not previously had the opportunity to explain.
It is tempting to throw colleagues under the bus. Avoid this unless absolutely necessary for your defense. Focus on your actions and your perspective. If you must mention others, do so neutrally: "Mr. X was present during the meeting," rather than "Mr. X is a liar." show cause response letter
[Signature] [Your Printed Name]