兑换前可退可改，兑换后不退不改。（天灾地动等不得已的状况以外）

兑换前可退可改，兑换后不退不改。（天灾地动等不得已的状况以外）

Results (English) 1:

Can be refunded or changed before redemption, non-refundable after redemption. (Except natural disasters and other unavoidable situations)

Results (English) 2:

It can be refunded or changed before exchange, and it can't be refunded or changed after exchange. (except for natural disasters, earthquakes and other unavoidable conditions)

Results (English) 3:

Before exchange, it can be refunded or changed, but after exchange, it can't be refunded or changed. (except natural disasters, earthquakes and other compelling circumstances)