I apologise for making you confused.
We've already reserved a room from 16th to 18th September.
I meant that we would like to late check in. Not early check in.
I understand that we can check in at 14.00 of 16th. But we will arrive at 26.00 of 16th (2.00 am of 17th).
Hence, I informed to you our late check in time and I would like to ask you NOT to cancel our room even if we don't show up at 14.00 of 16th.
I hope it's clear to you.