I call John Morris. Then one of the person's family members answers it.
Then what I should say?
Here are my possibilities. I'm not sure if they are correct.
(1) "Hello. Is John Morris there?"
(2) "Hello. Could you please put me through to John Morris."
(3) "Hello. Can I talk to John Morris?"
I'd use either 1. (with a 'please' added) or (a variation of) 3.
You would normally only use 2. if you expected the call to be transferred to another phone (extension).
The variation of 3. that I'd use is "Hello. Could I speak to John Morris, please?" (It is a bit more polite than "Hello. Can I talk to John Morris?")
People are waiting to help.