I have an unsent meeting invite that I created on Outlook for Windows.  It is to a recurring meeting, with multiple attendees.  I've changed the time, but I want to save the meeting invite without sending so that I can get more information before I finalize the wording and timing of the invitation.  Assembling the list of invitees was non-trivial, so I don't want to discard it and start over.

All the "Save" options are grayed out, and when I try to close the window it says that my choices are to continue editing, to discard the invite, or to send it.  

How do I save the invite without sending, and how do I avoid this problem in the future?