A direct debit is an instruction given to your bank to withdraw money from your account on one or more set occasions. A direct debit can be created for a fixed or varied amount, which makes the system perfect for paying mobile phones and credit card bills. The ability to change the direct debit is an advantage in planning for variations in the size of these bills.
Contact the business with whom you have a direct debit and request a copy of their direct debit mandate form. You will need to enter your name and bank account details, just as if you were creating a new direct debit, because the changing a direct debit involves ending the existing mandate agreement and replaces it with a new one.
Return the completed mandate form to the business. They will then complete their parts of the form, if necessary (some will already have completed their details before sending the form to you) and send it to the bank. It can take several days to process the direct debit mandate, and this is only possible on weekdays, barring bank holidays.
Contact your bank after a week to make sure the new direct debit has been set up and the old one cancelled. It is important to do this because processing errors can occur, and if the new mandate is entered without the old one being cancelled, you can end up paying two direct debits.
Some businesses, such as credit card firms, have online facilities for changing direct debits that will automate the mandate process. If this is the case, it may be possible for you to change a direct debit with that business by logging into your account on their website. This can speed up the process significantly.
Because it takes several days to process a direct debit form at the bank, it will not be possible to change most direct debits within a three to five days of a debit being due. It is therefore best to plan ahead when you know changes are due, to avoid inadvertently paying the wrong amount.