A spokesman for the organizing committee of the Toronto 2015 Pan Am/Parapan Games says six events have seen various sessions rescheduled since tickets went on sale last September.
Teddy Katz says ticket holders were informed of scheduling switches for diving, tennis, fencing, cycling, rhythmic gymnastics and racquetball.
Katz says the schedule changes are usually made at the request of a sports federation or to make sure the best possible athletes can compete.
But he says the tweaks to diving, which have seen ticket holders for a medal event relegated to watching a qualifying round, were made after organizers realized they needed fewer medal sessions for the event.
Katz also says organizers have sold about 400,000 of the 1.4 million tickets available for the Games, but says this doesn't necessarily reflect lack of interest.
"We know we won't sell out every venue — few games do. But gold medal matches are going quickly and, if you don't count preliminary soccer tickets, we're about 45 per cent of the way there," Katz said in a statement.
He also said it's common for major sporting events to see a significant surge in ticket sales in the weeks immediately before the games begin.
Refunds were made available to ticket holders whose original events were rescheduled, but Katz said most people chose not to take advantage of that option.
That didn't stop some disgruntled fans from airing their displeasure on social media, however.
"Disappointed that tickets for diving medals round got changed for prelim and can't buy tickets for medals @to2015 @TO2015Saad #PanAmGames," wrote one Twitter user.
"@Ticketmaster I purchased tickets for #TO2015 medal round for diving and #ticketmaster changed to preliminary for no reason at all!!!!!!!" wrote another.
The Pan Am Games will take place from July 10 to 26, and the Parapan Am Games from Aug. 7 to 15.
They will feature 51 different sports taking place among 16 host municipalities in and around Toronto.