Change ID action disabled in Employees screen

Hi,

I am trying to change the ID of an employee that has recently changed their last name, but the Change ID option is disabled. Is this a permissions issue or is there a different reason why this action could be disabled?

The image below is a new test employee I created to see if it is initially active for new employees, but it is still disabled here as well.

Let me know if you need any other information.

Kind regards,

Andrew