Your characters do not have to change to grow as characters. Most writers feel this is the only way to make characters grow, but, it is not so. Your character can remain steadfast, forcing them to get stronger on their belief systems and morals. This will help your characters deal with more complex situations you create for them. By making your characters grow, you can be as creative as you wish with no limits. The goal is to be able to write without limitations. You will have no boundaries as a writer.
Every character reaches a moment of truth. Depending on your writing skills and your creativity, you can bring your characters to that moment of truth by following real life situations. The steps that are taken to get from one place to another. In other words, what circumstances caused a situation in your life? This is always a good format to follow. If you figure out a situation in your life and how it came to a certain point, you will be creating steps to a complete outcome. use this as your guide.