Let us be clear on the differences between 'personality' and 'character.' The words are often used interchangeably and not always understood. Personality is our 'persona.' How we are interpreted by others. Personality refers to our outward behaviour, or appearance, our words, our actions. It is not how WE see ourselves.
So if we regard ourselves as shy, it is an interpretation of our character, not our personality. Procrastination is an interpretation of our ego-self, our self-image, how WE see ourselves. Others MIGHT see us as a person who finds if difficult to start a project, for example, or one who vacillates and can't make up his or her mind. They evaluate us by our personality - what we do. We evaluate ourselves through our own beliefs.
Our character, on the other hand is how we are at this moment in time. Character takes into consideration our skills, qualities and values as seen by that part of ourselves which is the real "I." It is NOT generally how we see ourselves but as we ARE in our present time as a human being.
So, to reiterate, our 'personality flaws' are our attributes which are judged by other people to be flaws. Our character flaws are those we personally perceive to be flaws; aspects of ourselves we would like to change.
We can change our characters by, first and foremost, making it a priority project to understand ourselves. And we can do this best by 'going within.' To 'go within' will probably involve lots of quiet, meditation, waiting for the answers that are inherent in all of us to surface. It will be the beginning of a life-long journey. So if you're interested...procrastinate no longer.