What is the difference between "amended" and "revised" clearances? Reading the ICAO Phraseology Reference Guide I saw the term amendment applied to clearances, and I got a bit confused about how to differentiate it from a revised clearance. What does each one mean? Are there any examples?
An amended clearance usually indicates something has been added to it, but the original content remains the same. Revised usually means the clearance has had modifications to the original content, including possible additions and deletions.