Can I change my seat?
cam-BIA-re — stress on second syllable. 'Posto' is POS-to.
When you want to move to a different seat after boarding, perhaps to sit next to a companion.
'Cambiare' (to change) is used for seats, money, clothes, and many other nouns. 'Il mio posto' (my seat) specifies that you want your own seat changed, not someone else's. Seat changes are usually possible once the aircraft door is closed and the passenger manifest is finalised.
Posso sedermi accanto a mia moglie?
Can I sit next to my wife?
The most common reason for requesting a seat change
C'è un posto libero vicino al finestrino?
Is there a free seat near the window?
Request a specific type of seat
Possiamo avere due posti insieme?
Can we have two seats together?
When travelling as a couple who got separated
Most airlines charge for pre-selected seats, but seat changes on board are generally free if empty seats are available. Families with children under 14 must be seated together by law in the EU — airlines cannot charge extra for this. Always ask the cabin crew rather than just moving without permission.