I'm seeing way too many comments about not being able to change the relationship. I was in a top school. I saw plenty of students change advisors and do fine.

I'm seeing way too many comments about not being able to change the relationship. I was in a top school. I saw plenty of students change advisors and do fine. You have to be a bit careful - your former advisor shouldn't be in your thesis committee, and some advisors are unwilling to take you if they think it will cause bad blood between him and the original advisor. But it definitely was done. Over and over again. Of course, it helps if the department is big (mine had about 100 professors).