Log into your account, then head to Plan and select "Edit Treats." From there you can update whatever's on your plan.
One thing to note: if you've got an order already processing, any changes you make won't apply to that one. They'll kick in from your next delivery onwards.
Once you're happy with your updates, select "Next" to reach the Review your Plan page and confirm everything's saved.
Any questions, our Customer Delight team are at feedme@differentdog.com or on 01952 456 850.