i want to cancel my bto order

See the following from Viewing & Changing Orders - Shopping Help - Apple

If your item is in Processing, you can cancel it online before it ships. Go to your Order Listing(Opens in a new window) page and select an item to see your order details, then select Cancel Item.

Once you’ve submitted your cancellation request, the status message of that item will read Canceled or Pickup Canceled.

If you canceled an item that was shipping to a physical address, you will not be billed for your item. If you canceled a pickup item, you may have been billed. We will initiate your refund immediately after you submit your cancellation request.

If you are unable to cancel your item online, you may be able to return it. To see if your item is eligible for a return, refer to the Returns & Refunds help page or speak with an Apple Specialist at 1‑800‑MY‑APPLE.

Hi Boycaboy,

To add to leroydouglas's post:

I would check your order online. If the cancel order button works, great.

If it doesn't allow you to cancel, you'll have to wait until the computer is delivered and then return it to an Apple Store within the 14 day period and then order the new 16" model.

I hope this helps.

Log back in—"Review Your Order" page—and look for the cancel order button.

https://secure2.store.apple.com/shop/np/sign_in/order