IN office 365 an existing calendar can be exported as either a PST file or a comma delimited text file and then import into another existing file. You open outlook, and then open the calendar and then go to file, and open file, Then go to open and export. At this point you have to make a choice as to either a text file or a PST. it will then create your file. It will ask for a file name. You can then store this file on file flash drive to move it to the new calendar. You will follow the some of the same steps to import the calendar into the system.