“Remember that to change your mind and to follow someone’s correction are consistent with a free will. For the action is yours alone – to fulfil its purpose in keeping with your impulse and judgement, and yes, with your intelligence.” Marcus Aurelius, Meditations.
No-one can make you change your mind: that power remains firmly with you and you alone. Apply logic and reason when considering what is important to you about a situation that makes you decide to stay with your initial choice, or to change your attitude and plan. If you cannot pin down what those reasons are, then you cannot be true to yourself.
If you choose to change your mind in a meeting or other discussion, it shows both humility (in being prepared to admit that perhaps your initial judgement was incorrect) and strength, as your ego is not threatened by acknowledging erroneous or naïve thinking. If you show others that you feel safe and secure with the possibility that you could be wrong, that in turn will help them be less defensive. And that’s where great dialogue takes off.