First, your diner's points can be transferred to most major airline FF programs at a rate of 2:1, meaning it will take twice as many points.

Next, you need to find an airline that has award availability to the destination you want for the days you want. Easiest way to do this is to call, explain you will transfer some miles from Diner's club, you just want to check availabity.

Now, here's the bad part. It takes a bit of time for the transfer to occur. They do have a way of transfering faster, but it costs extra. And Diner's also charges something like $0.95 per 1K miles transferred. During the time it takes for the miles to transfer, the award seats may be taken by someone else.

Most major airlines also have "anytime" awards which allow you to travel if any space is available. Those awards are typically twice as expensive as normal coach awards. If you do have to use this route, also check on first class availability, as it is usually the same number of miles for a coach "anytime" award vs. a first class "saver" type award.

Most airlines will not hold reservations for you if you do not have the miles in the account. I know United will not. Delta may, but I doubt it.

If southwest is an option for you, you can transfer segment credit there as well, and availability on southwest is normally excellent as they allow any open seat to be used for awards.

Hope this helps and good luck.

Billy