During checkout, you can choose to view different slots or you can select 'Change your delivery time' under the order info on the homepage of the website, or 'Change delivery' on your Orders page. Please note that slots are subject to availability so if you cannot find a suitable slot you may have to cancel the order if the original time will not work.
If you're past your cut-off you can contact us, here. One of our friendly customer service team will see what we can do. No guarantees but we'll try our best!