If a change is made within that minimum time period, the airlines see it as a whole new reservation. Therefore, the reservation must be cancelled and rebooked at the current price. This change fee is charged by the Airlines. Travel agencies have always been paid for their services. In the past we were paid by vendors such as airlines, cars, hotels, cruise lines in the form of commissions.
Travel agents are professionals who know the industry.
Being an affiliate of American Express, Menno Travel can pass on savings to you. The airlines demand full payment when the ticket is issued. If you purchase a vacation package, the payment plan varies. Sometimes only a deposit is needed at time of booking, and then full payment at a later date. Your agent will go over this with you.