能否由經濟客位update至Business class

Usually there is only 1 reason when airlines will upgrade passenger from Economy class to Business for free... And that is when Economy Class is overbooked on that specific flight, and that the amount of Economy Class passenger show up are higher than the Economy Class passenger avaliable... And providing that Business Class have seats available for upgrade...
And when the case above occur... There are a few things that airlines will look at before choosing who to upgrade... And they are as follow:
1) Passenger who hold a Full fare Economy Class tickets or a high sub-class tickets will have a higher chance when this kind of situation occur...
2) Passenger who hold a airlines Frequent Flyer programme... Usually higher tier means a higher chance in this kind of situation...
Usually airlines airport manager will hold this decision... And they will decide in between when the check-in counter close and when boarding begin... Those passengers who get automaticly upgraded will be given a new boarding pass at the boarding gates or being called up to the counter at boarding gate for a new boarding pass issued...
However, in case of huge overbooked, it is possible that you will be given free upgraded at the check-in desk, but this chance is much lower compare to at the boarding gate...
I would no suggest you to hasetate the check-in staff for a free upgrade, as they don't hold the right to get a upgrade... So don't ask would be a better option...
To become a member of airlines Frequent Flyer Programme, you can go onto airlines website where they will have the application form to fill in... Then you will be sent a temporary card via e-mail... When you have flown for a few times, you will then be issued a standard card...
For most airlines, there are many tiers in their Frequent Flyer Programme (FFP), and in my experience, holding the basic FFP card dont really stand a high chance... But when you get up the tier, the chance is higher if the flight is full...

有次由香港飛加拿大排隊check-in時地勤職員問搭客係咪趕住返去開工開學如果唔係改期返加拿大就有加幣300元或ungradeBusiness class ，到我入0左閘等上飛機時地勤職員又問我同一條問題，由於我要返加拿大開工而reject0左，如果下次再問我真係想嘗試坐Business class 滋味

閣下 一定要係 frequent flyer. 即係飛行常客. 仲要係該航空公司之會員. 咁先會有機會免費幫你 upgrade lor. 又或, 累積一定之飛行哩數, 換取客位升級 la.