So, couple of questions on a schedule change…

We had a schedule change on our return from Thanksgiving. 25 minutes later departure and arrival. Not a huge deal…I assume it doesn’t entitle us to anything change/refund-wise.

question is on notifications. I only know because we booked 2 tickets via Cap1 travel, which sent an email. The other 2 were booked directly on Delta, who hasn’t notified us at all. Is this normal.

Then, after looking online, seems our aircraft/seats are all the same, but when I looked at the seatmap (on app) it’s telling me that I need to call due to schedule change. Can I really not see the seatmap/change seats? Flying UA mostly, I’ve learned to check for additional changes once an initial change has hit. Should I be able to see the seatmap? Will that resolve itself, or does any schedule change result in an inability to change seats myself?