The title can mean: Fictional identity, fictional premise, gimmicks/promotions. Changing the title is fine as long as your fictional identity remains the same, readers can easily find it, and it represents your premise.
Refining or altering gimmicks is common, especially in web novels. Look at the RR to see how many titles have been changed or added, for example [dark fantasy progression - book 1 completed] and other gimmicks.
Or title information is added. For example, Naruto becomes Naruto Shippuden.
What is not normal is if you completely change the title. So the title loses its function as the identity of the story and the soul of the story.
For example, the title Naruto, you change to Saruto. Then this can be considered narrative betrayal.