You can modify your order preparation time following the steps below.
Log into your Merchant portal via https://merchant.yamimeal.com/web/merch/#/login
Click "Merchant Setting"
Look for "Preparation Time" in "Business Hours" tab
Within "Preparation Time" you can modify your order preparation time
Remember to click "Submit" to save and publish your updated information.
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.