If there's a passcode, ask Siri for help
Most people don't realize that even if you have a passcode lock on your iPhone, you can bypass it to do things like place calls or send messages — unless of course they've disabled this functionality in Settings. However, it never hurts to grill Siri a bit. Here are some things you can try asking Siri by holding down the Home button from the Lock screen:
"Call home."
"Call mom."
"Call dad."
etc.