I have two passengers flying from Lisbon to Montréal, connecting in Newark. The inbound flight (United) and the outbound flight (Air Canada) both operate on Terminal B. I telephoned United and got a man in Mexico who said that my passengers will have to exit Terminal B and then reenter it. I asked him if the passengers simply walked down the concourse to the Air Canada gate, whether they would be refused entry onto the Air Canada flight. He clearly did not know. He gave me two phone numbers to call, one for immigration in Newark that was not in service; and another for the United station in Newark, which rang without answer.

Anybody know what you really have to do, going from one international flight to another international flight on the same Terminal B? And whether there's anybody to call to verify it? I bought the tickets from TAP Portugal because the travel originates in Sevilla (Sevilla > Lisbon > Newark > Montréal). I'm feeling like calling TAP isn't going to produce reliable information either.