Unfortunately there is no built in way to export calendars from an Android device since these appointments normally sync to an account already.
To export the calendar you will need to go to the following link and install the iCal Import/Export 2 app from the Android Play Store: https://play.google.com/store/apps/details?id=tk.drlue.icalimportexport
Once you install the app launch it and perform the following steps:
- After getting through the initial greeting messages tap "Choose Calendar" then tap the calendar you wish to export
- It will take you back to the first screen. Tap "Proceed."
- On the next screen tap "Export."
- The "Current Folder" section will tell you where it will save your calendar file.
- (Optional) You can change this by tapping on the location and selecting a different folder.
- Below you can change the name of the exported calendar. The default is output.ics.
- Note: If you change the file name be sure to leave the .ics at the end.
- Finally tap "Export." Your calendar will export to the location you specified in step 4.