I think honesty is the key here. As long as you are up front with them about why you are opting to continue your lessons with another teacher what can they say? I think teachers take offense when students just stop showing up or make up a lame excuse about not taking lessons anymore.
If you are forthcoming in what you expect from your teacher and you are holding up your end of the deal by practicing it shouldn't come to you leaving for another teacher.
Sometimes we all get frustrated of our teachers and we think 'What the hell is he/she doing?? I am wasting time to be with this teacher'.
I don't know your situation, but perhaps instead of thinking like this, you should approach your teacher and let him/her know what is troubling you. face to face. While it may be awkward, your teacher will probably respect you more for being forthright with him/her.
Again, I don't know your exact situation, but being honest and straight-up about what I want has helped me to work through times like this with my teacher. I work full-time, run a business, have a family, etc. My teacher has many other students, gigs, etc., so it's easy between our schedules to drift off a little bit. I don't know about you, but I only see my teacher for 1 session a week, so at times we've had to "re-focus" on what we expect from each other. Honestly, the only thing that sucks about it is that I usually have to burn a lesson to accomplish this. But it is well worth it to me to ensure that I am on the right path and NOT WASTING VALUABLE TIME!
The only other thing I would suggest is to analyze the source of your frustration. What in particular is bothering you about this teacher?
I hope this helps you.
Thanks,
Ryan
Topic: Your teacher