Join Date: Dec 2002
Location: Danville, CA, USA;
Programs: UA 1MM, WN CP, Marriott LT Plat, Hilton Gold, IC Plat
Posts: 18,002
I can't address Amex, but the Chase 241 cert specifically requires RT travel to/from the USA. That being said, open jaw is permitted, I think on both sides.
Why would you cancel the return? You want to redeposit half the miles? Then yes, you'd have to cancel the entire trip and rebook the outbound, but the cost in miles will be the same as you can't use the 241. Or you could simply fly on your original ticket and be a no-show on the return.