What you described is possible and may work, but it's just as likely to fail and have you show up for your second night finding out your entire reservation has been cancelled. Like with so many things, this is a simple matter of calling the hotel and telling them what you want to do. "I booked two nights, can't make the first night, I know I won't get a refund but just wanted you to know I'm not a no-show and I will definitely be there for the second night." Easy, done.