I remember reading that if you use an android phone you can go into your app store and re-enable the ringer in the settings. No clue about iphones though.
for iphone u can go to iCloud.com and play a sound on your phone, even when its on silent
Here’s a way to return lost phones without even turning them on (and subjecting yourself to GPS tracking as a thief). Give the finder a safe, private and secure service to notify you of the recovery location quickly, and at no cost. My Stuff Lost and Found works for me…my lost phone found me the same day. The service is free and worldwide.