Please refer to the list below for non-amendable fields. 

1. MBL 

2. HBL

3. Vessel Code (Call Sign)

4. Vessel Name

5. Port of Loading Suffix or Port of Loading Code

6. Carrier Code

7. Voyage Number

If the field you need to update falls under the non-amendable category, kindly follow the steps on this link: https://knowledge-base.globaletrade.services/portal/en/kb/articles/how-to-update-changes-to-non-amendable-fields