Tried searching around but couldn't find the answer so hoping someone on this forum with experience can help answer. Booked a multi-leg mileage ticket in business from US to mideast and back. Looking to upgrade with miles to first and it appears if both legs are available for the two of us it would work out to 171.6K miles; however booking each leg separately, depending on upgrade availability, would work out to 202.8K miles (39K destination to DXB + 163.8K DXB to US). Currently only the shorter flight to DXB has upgrade availability at 39K for the both of us. The question is, if I booked that now and then availability opens up at a later time on the long haul leg, would they give me the discounted mileage rate which would work out to 132.6K or would they charge me the full amount shown for the individual leg? I have enough miles now to upgrade the shorter leg and in the next couple months will have the full 171.6K, but for fear of losing out am willing to book now and hope for the best in a couple month. Any thoughts?

I am in a similar situation with a trip to Australia in March. I have upgraded one leg on the outbound but the first leg still says not available. I have instigated auto-upgrade for the first leg and I recently managed to speak to an Emirates person who told me that if upgrade becomes available for the first leg the miles will be adjusted to the lower combined figure and to contact them to make sure that this happens. Still waiting for upgrade availability on the return as well. I have used auto upgrade successfully in the past but still check regularly to see if there is availability in case it does not work, which apparently it does not always!

They should give you the discounted 'through' rate when the other leg becomes available but you MUST do this via the call centre and INSIST you get the 'through rate'. IIf you do it on-line, they will NOT be able to retrospectively refund you the miles you 'overpaid'. Anecdotally, a few agents are not aware of this so you may have to be quite insistent (although the majority used to know how it works).

Echoing the advice of thijsseh and from my own experience. It is possible to get the through rate (lower rate) whenever the second leg becomes available, but you MUST call. It cannot be done online. There are very many good agents in EK call centres who can help to do this, but there are some who just are not as experienced. If you get one who isnt willing to do it, politely hang up and call again

I went through something similar booking MLE-DXB-IAD. I started with using miles to book J and then upgraded one leg and then the other came available. I did spend the extra miles to add the leg to have all of it in F (through many phone calls of the representatives saying I could lose my leg in F during the refunding process to rebook). I did provide feedback in the automated emails and got a phone call saying they could do it as I had wanted and they rebooked it all in F and refunded miles to my account.

This thread here has the discussion: Combine Business & First on Reward