Thank you all for your input. I ended up calling and did the call back. 56 minute wait time so less than an hour! After being transferred 3 times, I ended up with the most helpful flight booking agent I've ever had on any airline. She took care of everything.

I wonder if "Global Reservations" is a premium line because she empahsized doing everything quickly and seemed to genuinely feel bad when she put me on hold to sort out all the fare rules. Unknowingly I had booked a fare with some crazy rules So it was even more complicated to rebook than I anticipated.

This past time I was calling during normal East Coast working hours around 11am EDT. As far as I know there were no major weather events that would have led to high call volume. Once I called in the evening hours around 8pm EDT and that was the worst experience I've ever had with customer service. The third I think it was around 2-3pm EDT. When I called around 2-3 pm and had a long wait I ended up calling the European number and reached someone in 5 minutes. Very different customer service experience- no rush, calm, but ultimately couldn't make the change because it ended up being an Air France call center even though it was the Delta number.

I'll admit it is surprising to always have such high wait times and just figured that was the Delta way. I hate to think how bad it would be during weather delays!

I'll keep in mind Twitter for next time- I almost did that this time but wasn't sure if they'd be able to take money and I knew I'd at least have to pay the change fee.