The Bacs Reference (also known as the Payer Reference) is the only part of a Direct Debit Instruction which cannot be amended.
The only way you can change the reference is by cancelling the existing payer and setting them up again with the correct reference for submission to Bacs.
- Can my payers sign-up to Direct Debit online?
- Payer Sign-up Methods
- Can I personalise a paper Direct Debit Instruction?