If I am on a fork, can the reindex parameter fix this?

I’ve been reading confusing information online about what the –reindex startup parameter does. This link is not clear to me. https://github.com/bitcoin/bitcoin/blob/631df3ee87ec93e1fc748715671cdb5cff7308e6/src/init.cpp#L388 gArgs.AddArg(“-reindex”, “Rebuild chain state and block index from the blk*.dat files on disk”, ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS); So, if I am on a fork because a mandatory upgrade occurred, I did not know about it, and…