Changing the First Night after check-in

Q: I accidentally checked in someone with the wrong First Night, and now it won't let me change it.  How do I fix it?

A: It disables the First Night for checked-in reservations to help guard against accidental changes.  To change it, you just need to undo the check-in by clicking on the "Pending" box in the upper right Status area.  Then after fixing the date, click on "Checked in" to check them back in.  Be sure to answer the prompts carefully if it asks which date you want them checked in.