I assume that you would know to do a basic compare using Fileaid option '10'.
To get the required output:
1. Mention file1 as OLD dataset & file2 as NEW dataset.
2. Under 'Compare - Criteria Options' set 'Modify print defaults' to 'y'.
3. Set 'Print DELETED records ===> Y '
You will get the records from the file1 which are missed in file2.