I have a partner award booking on BA miles. EZE-SCL-JFK. Leaves EZE on March 15, leaves SCL on March 20 (inbound travel to EZE using AA miles ticketed separately).

Given the situation on the ground in Chile, we are reconsidering our vacation. Instead of spending nearly a week in Santiago/Valpariso, we instead would like to extend our time in Buenos Aires and then spend a few days in Mendoza en route to a much shorter (two-day) stay in SCL. There is availability on the BUE-MDZ legs, though they leave from AEP (not EZE) and on the MDZ-SCL leg.

Spoke at length yesterday with BA agent, who said that since BA doesn't have any operated flights into Chile, they have not issued (and do not plan to issue) change waivers as have most other airlines. He made it clear that BA would want $70 per person before changing our tickets.

I didn't get to ask my other two questions, so I thought I'd ask the forum first before having another round with BA, and be educated as to what I can expect before I call and spend another 20 minutes on hold.

1) AEP and EZE are the same city, but they are different airports. Even if we were willing to pay the fee, is this a change of "origin" which would require a cancellation and new booking as opposed to just a change? Our worry is that we have lost availability on the SCL-JFK leg, and so there's no guarantee we'd get it back if we had to do a full cancel.

2) The AEP-MDZ flight is Lan Argentina, which is also a BA partner but I suppose technically a different partner than Lan Chile. Will this constitute a change of partners (or two partners) for the purposes of the BA award?

I'm also relying on the OneWorld tool to determine that MDZ is a valid stopover: OneWorld has AEP-MDZ-SCL as a valid routing for BUE-SCL. My understanding of BA awards is that I will be allowed a stopover in both MDZ and SCL.

Thanks!