In this case, it is important to ensure that the person can retrieve the phone in a timely manner while protecting their privacy. You can follow the steps below: 1. **Don't view sensitive information directly**: Try to avoid looking deeply into the private information in the phone to protect the privacy of the person. 2. **Find contact information**: Check if there is any contact information in the phone, such as the phone number or email of relatives and friends. This may be the most direct way to contact the person. 3. **Social media**: If there are social media apps on the phone, you can try to find the person through these platforms and send a message. 4. **Tell the party organizer**: If the party has an organizer, you can report the situation to them and see if you can find the owner through them. 5. **Wait for the owner to contact you**: Sometimes the owner will come back to find the phone through other means (such as asking someone). You can stay at the party location for a while to make it easier for them to come back and retrieve it. 6. **Hand it over to a lost and found office**: If there is a lost and found office at your location, consider handing the phone over to them directly to ensure that it is returned to the owner safely. Before contacting the owner, make sure you do it in a way that respects their privacy and safety.