this message may be offensive
Can't believe I am doing this, but apparently I know people that thought reincarnation, rebirth and transmigration novels were the same thing and "why did you give your reading lists so much names?" so here we go.
Reincarnation is when you die and get reborn in a NEW life as someone/something else in a new or same world:
Emily dies, got reborn as a Jessica in a new/the same world.
Rebirth is when you die and got reborn again AS YOURSELF but usually as a younger (died as an adult/elder, is now a literal baby, child or teen) or past (died as an adult/elder, went back a couple months or years back before blah blah blah happened) version of themselves:
Emily dies at 24, got reborn as Emily still but a past/younger Emily
Transmigration is usually you NOT dying technically but being transported into a new world/person who typically has already lived a good bit of their life. Sometimes in your sleep or like you would blink and it happens:
Emily is working her shift, took a nap, woke up as Princess Zelda, like the exact same Zelda you see when Legends of Zelda opens up.
Hopefully I explained this right.