Example: BOS-ATL-LIM-ATL-BOS 4/1-4/8 $1771 ai. Fare code KNN07ANP but books in A, Z.
The fare rules specifically say:
ECONOMY WEB FARE WITH AN INSTANT UPGRADE AT THE TIME OF
PURCHASE TO FIRST/BUSINESS APPLICATION CLASS OF SERVICE
THESE FARES APPLY FOR ECONOMY CLASS SERVICE.
CAPACITY LIMITATIONS
PLEASE NOTE-
BOTH ECONOMY AND FIRST CLASS BOOKING INVENTORIES
MUST BE AVAILABLE AT TIME OF BOOKING.