Brasília is 4 hours ahead of Calgary
Best overlap: 8:00 AM to 2:00 PM in Calgary is 12:00 PM to 6:00 PM in Brasília.
Calgary and Brasília overlap from 8:00 AM to 2:00 PM (Calgary) to the equivalent 12:00 PM to 6:00 PM in Brasília — that's your meeting window. 6 hours of shared hours is more than enough — slot meetings wherever they're most convenient for the people involved. Note the seasonal wrinkle: when Calgary is on daylight saving and Brasília isn't, the gap between them grows or shrinks by an hour.