Booked CX PE flights - want to earn QFF SCs but want to upgrade using my Asia Miles.

Booked CX PE flights - want to earn QFF SCs but want to upgrade using my Asia Miles. Whats the easiest way to do that?

I apologise because I have asked this exact question here before but I can't find it. The suggested answer last time sounded like a lot of work (e.g. calling people). Is it possible to just turn up to the check in counter and ask them to do it there (seeing as CX accepts points upgrades at check in?)

Alternatively, what do you think the chances are that CX will give me a free upgrade to a QF Platinum member with a broken shoulder in a sling?

Better ring up CX. No pain, no gain - but I do hope that shoulder gets a speedy recovery!