Verb
To return a phone call.
John called. He asked for you to ring him back as soon as you arrived.
To make another phone call to the same person.
I had to ring you back because I forgot to ask you something important.
During the message, there will be frequent instructions to 'ring back in the event of problems'. Source: Internet
Harvey is released and given his ring back, after it has been examined; he is told that his friend has died of "heart failure." Source: Internet