再有 is a conjunction meaning 'if something happens again' or 'besides, furthermore'. It combines 再 (again) and 有 (have) to introduce a hypothetical repeated event or an additional point. You'll see it in conditional sentences — 再有 + noun/verb phrase + 就/都 + result — to mean 'if (something) happens again, then...'. It can also start a sentence to add another reason or example, like 'moreover' or 'what's more'.