创建模式–the default mode when you create a requisition and PunchOut to Bio-Rad.You can create and edit multiple shopping carts
编辑模式–allows you to edit or modify an existing requisition（prior to submitting）。You will be able to modify only the cart that you have PunchedOut to，and will not have access to any other carts
检查模式–when you PunchOut to Bio-Rad from a previously created requisition but without initiating an Edit session，you will be in this mode。You cannot modify any Cart contents
