In order to upgrade our tickets for a more comfortable return trip, my buddies and I went to the Delta Airlines Paris Office. The staff was really welcoming and gave us a rundown of all the possibilities. The costs and benefits of the upgrading were made extremely apparent. We ended up having seats with more legroom because we were happy with the selections. On the spot, they also printed our boarding cards for us. It was a really convenient and effective process. Having such excellent customer service in Paris was fantastic. The entire process was enhanced by the ease with which the office address could be found.