Really it depends on how your employer handles expenses for travel, and how lax they are about verifying receipts.

Several places where I've worked have had things in place that would stop this kind of thing from occurring (whether that was the intended purpose behind those things or not)

But if they only require you submit the purchase receipt, then you might be able to do what you suggest. But if there's any info on the receipt that could lead them back to the canceled ticket (confirmation number, etc) then it could backfire on you if they check it. They could probably even use the credit card transaction number to the same end. But I'd expect that to be more involved and less likely unless you did something to make them suspicious.

Possible? Maybe. Risky? Also maybe.

When you redeem these rewards miles, does it have to be for you, personally, or can you use them to buy tickets for someone else?

If you can use them for others, then a simpler way to exchange them for cash might be to just offer it on some online marketplace that in exchange for cash, you'll get airline tickets for them. You get cash, they get their flight at a discounted rate.

Basically no, this would not work.

That kinda stuff might have worked 20 years ago, when 'points rewards' were a fairly new concept and banks had not fully thought through potential ways to game the system, as you've described...

But they've now had about 20 years of 'clever' people functionally finding all the flaws, and they've since fixed them.

For starters, if you book a flight and then cancel it 24 hrs later, there is no actual guarantee you'd get a full refund.

Beyond that, if the payment was reversed or cancelled, so too would the rewards points be undone.

If you're going to try to get a cash refund... for a credit card txn that was cancelled...

That's basically fraud, you'll go to jail.

Unethical or not, this is stupid, unless you want to be investigated for fraud.

If you want the specifics, go find the exact, precise terms of the agreement you signed when you got the credit card with rewards points.

Chances are high that there is a lot of language that explicitly states that trying to convert points into direct cash is either not allowed, or follows a framework laid out in great detail, where the bank controls exactly what you can and cannot do with the points.

You might get away with it unless somebody looked. How big is the company you work for?