Typically, the airlines will transfer the account balance of a deceased spouse to the account of the remaining legal spouse, with the verification of a death certificate.
If the miles are to transfer to a child, the child requesting the transfer must prove that they are the only remaining child of the deceased, or alternatively have written permission from all other remaining children to transfer the entire balance to his or her single account.
Persons with a substantial mileage balance who wish to do something other than have their account transfer to their spouse or in equal shares to their surviving children, would be well advise to include their specific instructions in their will.
Life partners who are not legally married should be especially cautious in protecting this asset, as well as all their other assets, for the benefit of their partner, by virtue of a will or trust document.
Oh, GOSH, more free advice that is worth exactly what you paid for it.
[This message has been edited by Punki (edited 09-14-2000).]