Yes, that is usually the case in most FF programs.

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When working in a document or on an important piece of work it is imperative to back up or save your work. It is as simple as a click of the mouse. Every few months you can back up you entire library of files for protection.

Contact the airline. You will have to prove that both accounts belong to the same person. If they are in different names, you may have to provide documentation (such as a court order for a name change or a marriage certificate) to prove this. Each airline has its own procedures and requirements for doing this.

Assuming you're referring to miles in Lufthansa's own Miles and More program, the answer depends on what class you are in, what fare you paid, and what route you are flying. The low end is 10,000 miles: from full-fare (Y) or near-full-fare (B) economy to business class on a flight within one continent. The upper end is 75,000 miles: from other economy fares to business class, or from business to first, between Europe and Australia/New Zealand/Oceania. Other upgrades are between these extremes. The entire upgrade chart is at http://www.lufthansa.com/cdautils/mediapool/media_563080.pdf. (In general, airline Web sites are excellent sources of this type of information. It's pretty much always there, it's more authoritative than anything you read here, and you can potentially hold them to what they published if that's ever a concern.)

Delta finished the merger of the Northwest Worldperks FFP into its existing Skymiles FFP on October 1, 2009. At that time, one of three things happened. Users with a Worldperks account but no Skymiles account had only a Skymiles account going forward. Users having both who had previously responed to the request to link them had their Worldperks account merged into their Skymiles account. Users with both accounts that didn't link them ended up with two Skymiles accounts and had to merge them manually.

Black and orange.

A number of frequent fliers will have accounts with multiple airlines. Their primary frequent flier number is usually the one associated with the airline they fly with most frequently.

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