I will start this chapter by asking you: Have you signed a long time contract with your teacher? If your answer is no, well you can let your teacher go at any time you wish.
But even if it was common practice to sign piano-tutoring contracts, I’m sure that your current instructor would be considerate enough to have no objections. Please, by all means give a notice to leave. I also want to presume that by the time you expressed this reaction to your teacher, you would have spent a considerable amount of time thinking about it carefully before considering that now is perhaps the right time to do it. Make no mistake, piano is by now a part of your future self, thus your education as a pianist could be on the line. If you feel that your present teacher does not help you fulfilling your pianistic dreams satisfactorily, then you must change. And certainly, the only person that can have a pragmatic opinion on that subject is you; Not his or her previous satisfied customers (students), not the international press or the local chemist … the only person that should be able to judge this serious issue is ultimately you.
I have to admit that’s a tough task, but being a “big” pianist is to have big responsibilities. Many pianists I know survived many miserable years with their hated teachers because they didn’t have the nerve to release themselves from their tutorial “dictatorship”.
The reason behind your decision that your present teacher is good no more, can be absolutely any; it might be that you have realized that they can play banjo better than the piano, or because you don’t like the way they dress. Or that they have a foul breath. Or, because they have a black cat in their house while you would rather they had a white one; it is up to you. It is your money and it is your decision how to spend it.
However, hopefully the reasons are going to be a little deeper than that: for instance, your current teacher doesn’t know what he is talking about when it comes to Beethoven’s sonatas. Or that they don’t have enough things to tell you anymore that you don’t know already. Again, nobody but you has the right to judge that. At the same time, people should be supportive of your decision.
Leaving your teacher at conservatoire level can be extremely hard. Students suffer from that in many ways. For instance, students might dread having to face their teacher in the same environment again. Quite often they think that there is going to be a conflict between their new and their former teacher. It could also be that students are afraid they might get lower marks if they decide to change teachers. Yet, you mustn’t be intimidated. Most of the time, this is a simple secretarial issue and you get to change your teacher easily.
It is a fact that we all had teachers that we called mentors and others that we didn’t like. You are destined to have both. If you are lucky. A great teacher is one that stays in your mind well after you left him/her. You will always remember the things that you have learned. The same could happen with a “bad” teacher. You will also learn things, but mostly things to avoid.
To finish, be good to your teachers. Love them, show them respect and they will respect you back. They might even make you a better person.