aboran11
How “wrong” is that birth date? Smaller mistakes are not a problem, as long as your co-passenger can’t abuse that wrong date e.g. for a children instead of an adult ticket.
Generally spoken, once purchased, tickets can not be changed afterwards. Only cancelled/refunded if the travel date is still in the future (refund conditions vary depending on ticket type, see details => here) and then re-purchased with corrected data.