break or return from when expressions

You can use run with a return at label:

when(transaction.state) {
    Transaction.Type.EXPIRED,
    //about 10 more types
    Transaction.Type.BLOCKED -> run {
        if (transaction.type == Transaction.Type.BLOCKED && transaction.closeAnyway) {
            close(transaction)
            return@run //close if type is blocked and has 'closeAnyway' flag
        }
        //common logic
    }
    //other types
}