Allow meeting time options in Outlook

I'll start off by saying that this functionality is not built into Outlook, so it's more of a workaround than anything. You can create an appointment, export it to a file, then attach it to an email. If you do this for all the possible times you want to allow for the appointment, then attach them to an email, it will allow the users to select their desired meeting time from the attachments as if it was a meeting request. To do this

1. Create the appointment and invite required attendees, resources or yourself
2. Send the request. This way you'll be able to keep track of it, and will also have an appointment to export
3. Open the appointment from your calendar, then go to File->Save As
4. Save the appointment as an .ics file. It's a good idea to somehow incorporate the meeting time and/or date into the file name to make it easier to keep track of it.

5. Repeat steps 1-4 for each additional meeting time you want to allow users to choose from
6. Compose an email to those you want to give the meeting time options to and attach all of the .ics files you created for the meeting.

7. Send the message

When the recipients accept the meeting request, you'll receive a response like usual and the meeting will be added to their calendar. The appointment will also be updated in your calendar to show anyone who has accepted as an "Optional" attendee.

Like I said, this is a workaround. If you must allow time or date options for Outlook meetings, at least this will let you. If you want to see the original post where I found this, it is here