How Do I Change The Desktop Order in Mission Control?
Well i guess you're asking this because mission control 'automatically' changed the order you set up for your spaces.

You can't move them right in Mission Control but what you can do is disable that 'magic automatic ordering' in System Preferences => Mission Control => Disable Checkbox "Automatically rearrange spaces based on most recent use"
Then you can order them again using the Spaces Preference Panel.

Enjoy!