Adding or deleting items is not allowed after placing orders.
Before Merchants accept your order, cancelling order will not have any surcharges. You can check your order and, if desired, click "Cancel all" to delete orders under the tab "Live Orders". After that you can choose your desired items and place the order again.
P/S: Once Merchants accepted the order, cancellation fee may be charged from cancelling the order.
If you need further assistance for this request, please send a ticket to Yamimeal customer care representatives via https://help.yamimeal.com/hc/en-us. We will try our best to help you as soon as possible.