Hi Ronny,

The base columns here, specifically the ParticipantId column, is dictated via the Study Properties page.

If you go into the Manage tab for the specific study and access the Study Properties, you can edit what you'd like the column header to be called if you do not want it to be "participantId".

https://www.labkey.org/Documentation/wiki-page.view?name=studyProperties

Regards,

Jon