Question

You want to check if an order is already planned into a trip?

Answer

Go to ordermanagement and filter for that order, which you are interessted. Double click the order, so the order-detail window will open. In the upper left section, you will see the field "Status". This should be set to "Planned" if the order was assigned to a trip. At the bottom you can see in section "Planning information" the field "Trip ID" which points to the trip.