Every doctoral candidate is appointed a mentor. This mentor is not involved in the research, belongs to a different department, and is fully independent from your supervisor and promotor. Your mentor will advise and support you on all issues related to the organization and planning of your research and doctoral education, and, if necessary, refer you to relevant persons in the organization. Mentors also function as a confidential sounding board and help to anticipate possible bottlenecks. In the unfortunate case that you experience doubts or problems regarding the progress of your PhD, you can also ask your mentor to inquire into the interpersonal relation with the promotor and daily supervisor and act as mediator, but they will not take any action without your permission.
Please note that at any point in your PhD trajectory you can decide to change mentors.