You can save the updated Carrier O/B Intended only if the following conditions are satisfied:
The status of the selected outbound carrier is not Departed.
The selected unit is in the Advised or the Active state.
For a Through unit, the selected outbound carrier is the same as the inbound carrier.
If the unit is associated with a booking, N4 does not validate the updated Carrier O/B Intended or POD against the vessel visit specified for the booking. N4 assumes that the vessel visit specified in the Routing form (on page 1) is correct even it it does not match the booking.
When you update the Carrier O/B Intended, N4 also updates the O/B Actual Visit. It may or may not update the O/B Declared Visit and the O/B Intended Visit.
If an outbound visit is for an inter-facility transfer, N4 updates the O/B Actual Visit and the O/B Intended Visit (if the container has not been loaded yet). Otherwise, N4 updates the O/B Actual Visit and the O/B Declared Visit for the unit.