Invitation to send your PRO to Paris

[Confused]

I presume the procedure for the upgrade will be very similar to that for the Expert to Pro. So for those that have done this, how exactly does this work? To clarify what I am asking here, what I am particularly interested in is how the timing works. So, at some unknown time in the future Devialet will start to send 'invitations' to upgrade to customers. Lets say I receive my actual invitation on a Wednesday. I presume the UPS labels are delivered electronically, unless you also need to request packing boxes for the return? (I have kept both my inner and outer boxes) Anyway, the key question is this, you have your UPS label, boxes, and all is ready to go. Can you pick your timing? So with the UPS labels and boxes in your hands on a Wednesday, if you really wanted to still have your amps for that particular weekend, could you delay sending them back to the following Monday? Lets say that Wednesday was poor timing for any number of reasons, could you delay two weeks, three weeks or more for a better time? I have no idea how flexible this system can be. If it makes any difference, I do have a UPS depot within sensible driving distance of both my home and office, so could drop off myself if that helps in any way. I am just looking for a bit of experience from those that have been though this procedure before with the Expert upgrades. Be gentle with me, this will be my first time! Just to explain, I can look forward a few months now, and see that there will be some reasonably convenient times to send the amps back without missing them too much, and also some times when it will be extremely annoying to be without them. Any ideas?