Accidental PNR split?
 

Here is the story:

My wife & I were on the same PNR for our June flight (nw tix, dl outbound, nw inbound). I had some last minute business came up two days ago that might require me to change the outbound flight, so I went to nwa.com to get a quote for the possible change (only for my outbound flight, never went all the way, i.e. did not confirm any change).

Today when I checked our reservation again, the confirmation # has changed & it's only showing 1 passenger – myself, then I logged into here WP account & saw the original confirmation # is still there, but listed her as the only passenger. Called nw & was told indeed the pnr has been split & the csr couldn't tell me who changed it. Has this ever happen to anyone?

Never had that happen, but if it's a concern you can always have the PNRs "linked" which is really just a comment added so the two PNRs noting you're traveling together.

Also, if you do OLCI or at the kiosk, and only check one person in (even if you don't complete and cancel), you split the PNR.