Originally Posted by RealHJ

Go to airfrance.us, join Flying Blue, then search for award flights there (it will search both Air France and KLM) out of the nearest major airport, and then on delta.com just the local connecting flight. Once you find flights avaialable, call Delta and tell them exactly what you want. Unless you have checked availability yourself and give to agents the exact flights you want (date, airline, flight #) and if they say no, insist that they check in the proper fare class (often they don't - so you need to know what fare class each flight has to be in), you can't really get anything booked. You need to do the agents' work for them and search and exhaust all the possiblie routings for availability; they will not (unless you get a former NW agent) do it for you.

Also, as someone else here has said, check on delta.com flights to PRG, and if available then call DL to see can they book you on that plus the Czech Airlines local connector.