The Grand Ayatollah Seyyed Sadeq Rouhani answered a question about changing Marja Taqleed.
Question: Can I change my Marja Taqleed?
The Grand Ayatollah Seyyed Sadeq Rouhani: If your Taqleed has been correct and according to religious rules and then you realize that another one is more knowledgeable or God Forbid the first Marja is not just, you must back out. And if your Taqleed has not been correct, must ask the experts and with their opinions, choose your Marja. However, it is not up to you that any time you like, you decide to change your Marja.