Hello,how are you?
-To answer that question, use I am fine, thanks.or I am good, thanks.If you are not well, you could say Not great, really.or not too good, actually.
- If the person you want to speak to is not there, you may hear, Sorry, he's not here.or Sorry, she's not in.
-If you want to ask whether you can do something, use Can I leave a message? Can I call back later? or Can I give you my mobile number?
- To ask someone else to do something, use could you..? Could you ask her/him to call me please?
When you end a telephone call, say goodbye or bye, thanks for your help,Ok then, goodbye, see you soon, say hello to.. Give your (father-mother)my best wishes!