It is possible, but it takes time and practice and effort. You probably have heard of assertiveness training. There are groups and classes and books and articles, or it can be a part of individual therapy too.

Basically, when your underlying attitude is "I'm not okay - everybody else is" your communication tends to be passive and you try to stay out of the way, and you feel unheard and don't get your needs met.

The other extreme is aggressive, when people assume "I'm okay but you're not" and bulldoze their way through and try to force people to see it their way. Combinations of the two are also possible.

The middle ground is "assertiveness." When we are used to being passive, being assertive doesn't feel right to us. It can feel like we are being aggressive, and we don't want to be aggressive. But when you get used to it you can tell the difference. Assertiveness is respectful to yourself and also to others. The attitude is "I am okay and you are okay."

How to do it takes a bit more than I can explain in a post, but you will find lots of information if you look for it, and then just practice it, starting where you feel safe, and working it in so that you can use it more of the time.

Basically, you keep your body posture, hands, arms, etc. relaxed - nonthreatening but also not defensive or timid. You make eye contact with the person you are talking to. And you use "I statements" to tell them what you feel, think, need, etc.

You might have some anxiety, as changing yourself and talking to people more directly can be scary, especially if you are prone to anxiety. You can do it though. Assertive is actually the most peaceful way to interact. Passivity feels peaceful because you let others have their way, but it's not respectful to you and it discounts others' ability to listen and be fair with you.