I've followed the name changes of my maternal grandfather's surname.
My grandfather, with the last name Leapman' had led me to believe that the name was originally 'Liebman', and had told me that we have relatives by that name in Buffalo. He also led me to believe that this name change happened at Ellis Island, and that an immigration official had done it. Or maybe I just assumed that this is what happened, because of the Ellis Island meme.
The story is far more ordinary than any of this. In the Jewishgen Litvak records, the name is Leybman. On the ship manifests I've found, the name has been either 'Leibman' (the exact way a German-speaking clerk would write it down), or a few times as Libman.
Then I can see from various US censuses, that the spelling of the name became inconsistent here in the US. Sometime my grandfather's family used 'Lipman' and sometimes 'Leapman'. The Buffalo relatives generally used 'Lipman'. After a while, the Pennsylvania relatives settled on Leapman.
I myself, when looking over ship manifests, am quite amazed how surnames are spelled consistently, even complicated Polish surnames. I believe the German and American clerks who were doing all this writing made every effort to not change anything.
And, as it turned out, it wasn't Ellis Island at all. Most of my maternal relatives came through the port of Philadelphia. But that is another can of worms.