Translation of substitution in German

It is very important that you know the exact needs of your students. There are a lot of details involved in this learning process. One should always check all options and decide what is best.
The problem is that we are planning day by day and in our region (Maine, New Hampshire...) most hotels are 'by request' and not by 'space available'. I could do it but I would need to do the follow up.
She could not join me since her flight to Israel was supposed to leave in less than 48 hours. I helped her carrying the bag to a hostel in Cancun and we went together to the airport. I postponed my flight again.