it is not uncommon for appointments to be canceled or changed at the last minute - in this case, the proper thing to do would be a polite rescheduling without discussion, or questions as of the reasons of the cancellation - on the other hand, if the situation arises where one is kept waiting, feelings of impatience or frustration should be kept hidden.  

cariocas view time as something which is outside of their control, and furthermore acting out will only make one appear foolish - understanding the relation of time to all aspects of the culture are important to ensure business transactions run smoothly.

lastly, cariocas are extremely friendly and welcoming - in relation to these characteristics they generally do no like doing business with individuals who seem like strangers as they often feel rushed and not understood - a good idea for visitors in business situations is to commit time into forging strong connections because these relationships will make the difference between success and failure.