Below is a corrected, professional version of your email, followed by a brief, simple explanation of the main edits so you can learn from them.

Dear Cathleen,

Thank you for your quick reply.

I may not have explained myself clearly. Our accountant does not need a new invoice; we need a separate document — a credit note — that records the refund as a distinct transaction. For tax purposes, the original invoice must remain unchanged in our books because it is finalized and cannot be deleted. The credit note should reference the original invoice, state the refund amount (€9,950), and explain the reason for the refund: a partial reimbursement of the exhibition space rent due to our non‑participation in the fair. The credit note will offset the original invoice and create a clear audit trail, showing the tax office why we paid the original €14,047.95 and subsequently received €9,950 back.

I hope this clarifies things. Please let me know if you need any additional details.

Best regards,
[Your Name]

Simple explanation of the main changes (step by step):

  1. Made the request clearer: I moved the sentence that describes the credit note so the purpose is stated early and clearly.
  2. Replaced parentheses with em dashes (—) to make the sentence flow better and look more professional.
  3. Used consistent wording and polite, formal tone (for example, "distinct transaction" and "reference the original invoice").
  4. Kept the numbers consistent and clear: €14,047.95 and €9,950, and repeated the amounts to show the cause and effect (why money was paid and why some was returned).
  5. Added a placeholder for your name and kept the closing polite and concise.

If you want, I can add the exact invoice number and the date into the paragraph for the credit note reference — just tell me those details and I will insert them.