Direct Debit cancelled, reset invoice to pay again

Client had paid by gocardless direct debit on a single invoice but then cancelled the direct debit by mistake. They wish to repay by gocardless but don’t now see the button to pay when they view the invoice. When I view the invoice it show that it is due to be paid by direct debit…how do I reset this so that the client can re-setup the payment?

As long as the invoice is flagged as outstanding the client should see the option to pay by GoCardless:

If this isn’t the case ping me over the invoice number and I will take a look.