Originally Posted by Thunderroad

Very sorry to hear about this, but I'm a bit unclear. TK canceled your award tix because of its schedule changes? Is there no way to get UA to restore availability for a schedule that suits your needs OR for you to adjust your schedule to accord with the TK changes?

In any event, if in fact there's nothing you can do, I'd suggest a few approaches:

1. While you can of course simply call UA and BA, or check their websites, to see about award flight availability, a possibly more efficient way to approach this is to turn to the very efficient awardnexus.com site, which is great for award flight searches. For some limited, initial use it is free for FTers. That might even be sufficient for your needs. But if not, for $50 you get significantly expanded use, plus the ability to get email alerts if award availability opens up on flights you designate.
2. IF seats are available, your BA miles can get you NYC-LON-MLE on BA and then CMB-HKG-NRT on CX (or conceivably CMB-NRT non-stop on JL, if it flies that route). BUT lots of problems with the BA option: I believe award availability LON-MLE is very limited, plus could be that LON-MLE goes from Gatwick after you arrive in LON in Heathrow, plus BA has surcharges of at least a few hundred dollars for award tickets.
3. A better option might well be taking CX to get to HKG from the USA and then on to CMB (and then a short hop on Sri Lankan Airlines to MLE), and then as per #2 taking CX and/or JL to get to NRT and back to NYC. You'll avoid the BA award fees even though you'll have to pay for the CMB-MLE flight and you have enough miles to fly CX F transpacific, which is one of the great commercial flight experiences one can have. (So good that I'd consider flying NRT-HKG-USA in CX F if that's an option.) Of course, this hinges on CX F (or J) availability. But CX F availability does come and go, so it's not out of the question. Also, you'd want to leave a big gap between your CX arrival and Sri Lankan departure, to allow for delays, etc.
4. Other variations on these themes using your BA miles include taking AA as far as LON or exploring options with other OW partners. But this brings me back to using awardnexus.com to research what is or could become available.
5. By the way, I assume that your CMB leg includes a bit of time exploring Sri Lanka. If you're just planning on spending four days in CMB, you're better off spending those extra days in the Maldives or Japan.

Hope it all works out!