Do suicide hotlines call 911 on a caller who is in immediate danger of harming themself ?

just curious and do they trace the call or will they just go to your home address, so if someone was to ring on a pay phone or something then they call 911 to help (but the person doesn't want help and hangs up, and blends into the public how can they possibly find you? or do they ask for the info when you first ring up?