I understand that Delta has a policy against a nonrev flying with a under 6 child in 1st class.
I want to go to the D.R. with my 2 yrs old.
I have taken her with on flights that all had main cabin seats open.

What happens if there are 1st class seats but no main cabin seats left.
Does a main cabin rev passenger get moved or are we denied boarding.
The flights I want to take STI --> JFK there are no upgrades moving up and all nonrev's get 1st class.

Thanks.