Https://thwarts.cee.illinois.edu/files/2025/06/travelusa-four-ways-how-to-call-to-agent-at-united-airlines-phone-email-or-chat-a-step-by-step-guide.pdf https://thwarts.cee.illinois.edu/files/2025/06/travelusa-four-ways-how-to-call-to-agent-at-united-airlines-phone-email-or-chat-a-step-by-step-guide.pdf