TK changed my YVR-ORD (layover)-IST flights next week to a layover at ORD of 30 minutes (original booking had nearly 3) and so their system won't let me accept the existing flight while their CS tells me that my only option (other than a refund - which I can't accept as I have plans beyond IST on this trip) is to accept a 9am YVR-SFO-IST (AC then TK) option that absolutely does not work for me.

As such, I was wondering what nightmare will I experience if I were to still go ahead with my existing confirmed reservation of YVR-ORD-IST?

YVR-ORD is via UA so I'm guessing that flight will still go ahead and I will then be stuck in ORD.

Will the responsibility then fall on TK to find me an alternative ORD-IST flight, in this case?

P.S. The ticket was booked via TK Miles & Smiles (pre-devaluation so there's another reason I refuse to accept a refund)