As far as I’m aware once you’ve instructed the company to setup the new DD it can take a few days to appear in the app.
If you have informed the company of the new account details for the DD you will be protected should it not go through due to the Direct Debit Guarantee. So your credit rating wouldn’t be effected or any late payment fee’s shouldn’t apply should it not be setup correctly or the payment fails, unless you don’t have enough funds in your account.
Can anyone confirm?