Jeremy isn't much help here; he either can't remember or refuses to think about it. We'll need to find out on our own.
Hint 2
Jeremy asked you to bring him his notebook from his office at the City Post. That seems like a good place to start.
Hint 3
The receptionist very rightly won't let Rosa into Jeremy's office, but she can't stop someone she can't see, especially if that someone can float through locked doors.
Hint 4
As Joey, go upstairs into the room marked "Junior Reporters." Jeremy's computer is the one in the middle of the room with a notebook leaning against it.
Hint 5
You can't do anything with the notebook -- Joey's blowing just rustles the pages -- but there's a post-it on the computer. Right-click on that to read it.
Hint 6
If that's Jeremy's last appointment, it's significant. Leave the newspaper and go to High Line (which is a park on an old elevated train platform in New York).
Buy me a coffee