I have manifests for my great-grandfather that seemingly show him coming over more than once. Once by himself, once with his mother and younger siblings. The details of the manifests seem to show the same person, with details like age, destination, and relatives matching up.

Question: why would someone have come over more than once, and if they did would they have had to go through the Ellis Island process each time?

Travel was from Poland (Russia) to the US.

Thanks!