user_query: call sister on zoom
response_text: Sorry, who do you wanna call?
user_query: call sister on whatsapp
response_text: Before I can help you make video calls from this device, you'll need to install the WhatsApp mobile app.
user_query: call sister on skpye
response_text: Before I can help you make video calls from this device, you'll need to install the Skype mobile app.
User: call sister
Parse: Initiate_call ( callee Personal_contact ( person « sister » ) )