Инверсия в условных
Were I to… / Had it not been for…
В книжном стиле if убирают, а глагол выносят вперёд:
- Were I in your position, I would refuse. (= If I were…)
- Were he to apply, he would certainly get the job. — гипотеза о будущем.
- Had it not been for your help, we would have failed. — если бы не ваша помощь.
- Should you need assistance, please contact us. — вежливое «если вдруг».
Это язык договоров и официальных писем. В разговоре звучит нарочито.