Can you explain the action codes in ACE Ocean rejection messages?

Can you explain the action codes in ACE Ocean rejection messages?

Here’s a general overview of action codes used in AMS for ocean manifests:

A01 – Add: Used when submitting a new Bill of Lading to the system.
K01 – Cancel: Used to cancel or delete a previously submitted Bill of Lading.
M01 – Modify: Used to modify a previously submitted Bill of Lading.