Final preparations... a northamerican's perspective

Last night I am checking into the additional apartment for the group's arrival. It is late and the last minute details a bit more complicated when you do not know the system. Is it necessary to change the locks? I mean this is a short term rental apartment, like weekly. Do they do this every time? I wonder. I contracted with a remiss service for transportation to and from the airport. Again a bit complicated because I will need two cars arriving an hour apart. They give me a card with their number that says 24 hour service, smile, and say call anytime. I just called to confirm and noone answered. Gabriela would smile at me and say "This is Argentina, mi querida (my dear)! You Americans..."