Of course it can be changed. You are a postdoctoral fellow in a university. Generally speaking, you should contact your tutor before entering the post-doctoral mobile station. It seems that this tutor is the only one you are most familiar with in this school. If it is not good to change tutors, in principle, you can contact another tutor to discuss, stop your current postdoctoral work and re-enter the station to be a postdoctoral fellow.

However, it is not good to change a co-tutor in a school. Anyway, the postdoctoral fellow does his own research, and the tutor only provides platform funds, so bear with it. Two years passed quickly.