Gate agents handle a lot of issues:
* Seat assignments for those who haven't gotten seats or would like to have their seats changed
* Adding passengers to the standby list and confirming standby passengers
* Processing upgrades
* Rebooking passengers who might miss connecting flights because of delays
* Providing compensation to passengers who have been bumped off of a plane, or those who are eligible for meals vouchers, hotels, etc., in the event of delays where the airline is legally responsible
* Checking passengers' passports and other travel documentation if it wasn't verified at the check-in counter
* Confirming that passengers' carry-on bags confirm to the size and weight requirements, and tagging them in the event they need to be rebooked.
* Adding frequent flier numbers to passenger records.