My sister is visiting from India. They finished their USA and Canada tour. They had only single entry visa for Canada but when they were crossing from US Niagara Falls to Canadian Niagara Falls they asked the officer at Canadian custom about multi entry visa to Canada. Officer told them that they do not need it they can come as many time as they want as long they are in USA and until their ticket expires. They went back to US then after month they wanted to visit Canada, they bought the ticket to visit us. They went to Atlanta Georgia airport to board the plane, there they were stopped by Continental Airline were told that they can't go to Canada because they have only single entry Visa. They showed them the letter they received from Canadian consulate about multi entry still Airline would not give them permission to go. What they should have done in this situation. Also what can they do now to get the multi entry visa for Canada? It was very disappointing for us and for them because we both were looking forward to the visit. It cost them lot of money, time and frustration. I would appreciate you help on this matter.