As a newly minted Elite I have never had the opportunity to use an upgrade certificate. I'm heading to Vancouver in October and will be using one if the God's of the I Class deem it appropriate.

My question is - does the 4 day window open at 48 hours prior to scheduled departure or at 12:01 am 4 days prior to the departure date?

I tried a search but couldn't find an answer to this.

Thanks!