Depends on if your contacts and calendars are in the cloud (iCloud/gmail/outlook). If they are, you could completely wipe the device and then simply re-add the cloud based accounts. But you'd need to copy the photos from the device and then sync them back to it
You can wipe your phone through settings -> general -> reset -> erase all content and settings (backup your phone first though).
Once this is complete you can set the device up as a new phone and then pull all your calendar and contact information from the cloud.