I need a one-way ticket from FCO-MIA this spring (returning from a trans-Atlantic cruise). The fare for a convenient one-way biz class ticket is around $5000, but a RT ticket departing on that same flight prices out to around $3300. Obviously I could buy a RT ticket and throw away the return flight, but the more intriguing question is this: After completing the first leg of the trip could I change the "return" flight to a transcon domestic ticket? And if I could, would the value for the unused return flight (MIA-FCO) be 1/2 of the original RT ticket cost (i.e. $1650 in this scenario)?