Outlook: Why am I unable to amend appointments in another person's Calendar?

If you have access to view another person's calendar but you are not able to make changes to appointments despite being authorised to, you can fix this by:

• Asking the owner of the calendar to go to Calendar Permissions when in Outlook;

• Selecting your name from the list, or adding your name by clicking Add and selecting you from the list;
• Click on Permission Level and select "Editor" or
• Make sure the "Edit All" button is ticked against your name, to make sure your permission level is high enough to be able to make changes.

• Click Apply/OK

This should then allow you to edit appointments as required.