Final answer:
The informal sentence is transformed into formal English by changing the wording and structure, suitable for professional communication.
Step-by-step explanation:
The informal sentence 'We are not going to renew the sole representative agreement again because you haven't produced enough business for us.' can be transformed into a more formal version as follows: 'The company has decided not to renew the existing sole representative agreement due to the insufficient business generated on our behalf.'
This alteration elevates the sentence's formality by adjusting the word choice and the structure, thereby making it more suitable for a professional or formal communication context.