Every action, "Karma" is carried out in four steps:
Ichha, Sankalpa, Vikalpa and the Kriya........ Desire, determination, planning or the method and then comes the physical action.
For example, while reading a book, I suddenly had a desire to have a cup of tea. But the next moment I thought " Nah..... may be later." So that was the end of it. The Ichha or desire did not go to the next step and never turned into a real "Action".
In the second scenario:
1. Ichha (Desire) ......... To have a cup of tea.
2. Sankalpa (Determination) ....... "Yes I definitely want
The next step would be:
3. Vikalpa (Planning / method) ...... how to get it.
There could be many different ways to achieve the goal.
I could go to the kitchen and make it.
Ask someone else to make it for me.
Go out and get it from a shop or it might be possible to order it over the phone and have it delivered to me.
So the actual "Karma" the” physical action" may vary depending on our Sankalpa and Vikalpa.
Strong desire, sincere efforts and constant practice along with proper guidance are required to achieve any goal.
With continual practice, a right handed person can learn to write and do other things with left hand. It might be hard but concentrated guidance thru conscious mind; it can be learnt over some period of time. Similarly with continual practice, we can change our karma and habits by changing the patterns of Ichha and Sankalpa, the desires, and determination of turning the desires into action.
We may not have much control over thoughts or desires, but we can control the Sankalpa or determination. By consciously watching our thoughts and desires, we can choose which ones to turn or not to turn into action.