To change your payment date, head on over to Manage My Booking, Select ‘Menu’ at the top of the page then 'Payments' on the relevant booking and then 'Change Instalment Dates'.
From here, you can select a date from the dropdown of when you'd like future payments to be taken.
Once you're happy with the new payment schedule, click ‘Update Payment Date’ to lock it in.
Please also note payment date of your final instalment cannot be changed.