update
 

After taking 2 days to respond, Citi said that the AU has never been eligible for the companion pass even if added prior to the change of benefits. After the tedious experience of using the companion pass on the primary account earlier this week, maybe that isn't a big loss... I have a feeling we won't be renewing. If anyone has had a different experience, please let me know. Thanks!

I have the Prestige with my wife as AU, my wife has the Prestige with me as AU, the accounts were open early 2014, we both received the companion pass for the AU, so we had a total of 4 companion passes, 3 of which we have used during 2015.

To be honest, It's really a tedious task to book companion ticket through citi concierge. I used mine, but not got a chance to use my AU's before it got expired because we cannot find the right fights they provided through emails. So we ended up with losing it which we paid $50 for the AU. I tried to call them for this trouble but no one tended to refund me the AU FEE since my AU didn't use the ticket. I canceled my AU during renewal since there is no perk anymore... anyone had similar experience ?

3 weeks ago I booked as the AU on my fiancee's Prestige card. The AU has most definitely been eligible for the companion ticket in the past -- HUCA.

I used both Primary and AU's companion tickets during the last week. It was a frustrating process. And one of the companion tickets was used for a flight departing and returning in December. It seems that flights should be booked (and not "completed" as it was in the email they sent to explain the changes) by October 18. Or perhaps I was lucky...

My Prestige card was approved in August 2014. If I add my wife as an AU now, will she be eligible for a companion ticket before 10/15?

No.

How do we know if we can still qualify for this or not? I had the citi prestige for five years ago but never used this offer

If you still have your Prestige card and its anniversary is before October 18, you are eligible to use this benefit until the anniversary of your card. If the anniversary of your card is after October 18, you are not eligible for this benefit.

Has anyone had any success booking a flight that did not complete by October 18? Does only the outbound leg need to be by that day? I have one ticket left I would need to use by the 27th.

It appears there is no way to book something rather expensive and then exchange for credit or change dates after booking?

It is too bad we are approaching the end of a fun era in companion tickets. Congratulations to everyone that went hard!