In theory, it is possible to change doctoral supervisors, but it is very difficult to implement. Here are some reasons that may make it difficult to change tutors:

1. There are enough students under the names of other tutors who are unwilling to accept other students.

2. Due to my own professional limitations, I can't find a tutor in the relevant research direction.

3. Other tutors are worried that they will offend the original tutor after accepting it.

4. The school does not encourage or support the easy replacement of tutors.

A doctor refers to a person who has a doctorate. Doctor's degree is the highest degree in higher education, which usually needs to be obtained after completing certain research work and thesis defense in universities or research institutes.