You can edit your order up to 4 days before your delivery date. For example if you receive your delivery on a Sunday, your deadline for editing your order will be midnight Wednesday.
You can check your cut-off time for editing a delivery, by logging in to your account and reviewing your 'Upcoming Deliveries'.
If the deadline to edit your order has passed, it will state 'this box will be with you shortly' (see example below).
If the deadline hasn't passed and there is still time to edit your order, it will state the deadline for editing the order (see example below).