In general, tickets cannot be returned for a refund – once bought, they’re final.
Reselling tickets on unauthorized platforms is not allowed and may make tickets invalid.
However, you can transfer your mobile tickets to someone else using the official ticket app (see Mobile Tickets section below). This is the only approved way to give a ticket to another person.
If the match is canceled or you purchased optional ticket insurance, see the Refunds and Ticket Protection question.