Can someone with mild Parkinson's or essential tremor will his hand to stop shaking for a while?

On those occasions when I get a small tremor in my hand, I can, with concentration, make it stop shaking for a while. I wonder if that rules out Parkinson's (or essential tremor). I was diagnosed a couple years ago with Parkinson's by one neurologist, but the second opinion neurologist said I did not have Parkinson's (or any other neurological condition). Since they cannot seem to agree, I look for things that might help me to know for myself, like for example the fact that I have no progression of symptoms nor any other symptom than an occasional hand tremor. To me, I have neither Parkinson's nor essential tremor.

I see no point in getting a third opinion because the first two neurologists were totally unbelievable since they could not agree. Probably the third doctor would not be any better.