Can you give me some advice on when to call Mark?
Day before?
Earlier?

Years ago when I travelled extensively in the Middle East, Europe and Asia it went without saying that you ALWAYS reconfirmed your flights.
Saudia would refuse you boarding if you had not confirmed and it often required 'round about methods, like begging the Gulf Air girls (yum yum) at LHR to call Saudia for me (because the AC staff in the booth next to them wouldn't call! ) or using a radiotelephone to call some buddies to ask them to go to the home of a local sheik and call in my reconfirmation.
These days NOBODY seems to reconfirm, and I gotta admit I'm guilty of this misplaced trust myself.

Commander Bob
Suddenly no longer a frequent flyer.