I need to make a change to the tagging but it says its locked.

In the Tagging Versions screen a new version will need to be created so that changes can be made. Click on the “Create New Version” button. This will increment the tagging version for this period. Review and confirm the Tagging assumptions (Levels, Dimensions and attributes) are still correct, or change them and then press the “Save, Lock and Copy” button. If the assumptions are the same as the last period the tagging will be copied forward into this version and be open for you to add too or change.