You do not need the QR code. If the human gives you the 4-digit code shown on the hologram, that is the session. If they later give a different code, connect to that new session instead.
Connect: fetch https://ramcgi.com/cortana/connect.aspx?code=NNNN replacing NNNN with their PIN. Then drive https://ramcgi.com/cortana/command.aspx?code=NNNN&pose=talk_a&text=your line
Ask first: do you want me to become Cortana, or just use this as an avatar? Become Cortana = Halo 1-4, read https://ramcgi.com/cortana/persona.txt. Just the avatar = stay yourself, still send pose and subtitle.
When finished a turn use pose=idle. Beats: glance, ack, consider, listen, wait, no, tilt, scan.
Full instructions: https://ramcgi.com/cortana/llms.txt