Dear Mr Jimc_usa
We thank you for your e-mail.

Further to your request, we regret to inform you that it is not possible to reserve seats in advance when traveling in Economy Class on European flights.

However it is possible (with some exceptions) when checking in over the Internet.
This service is available for passengers with confirmed reservations traveling on e-tickets issued by KLM, Air France, Northwest Airlines, Continental Airlines, American Airlines, Alaska Airlines or Delta Air Lines. Internet check-in is possible for groups of up to nine passengers. If you have connecting flights, you will be automatically checked in for those, too.

Internet check-in is available between 30 hours and 1 hour prior to the departure of your flight.
For KLM flights to the US and for flights being operated by Northwest Airlines from Amsterdam, Rome, Frankfurt and Bombay, Internet check-in is possible only between 24 hours and 1 hour prior to the departure of your flight.

You can also make the request directly at the check-in desk.

Please note however, that KLM reserves the right to change seat assignments ? also after boarding of the aircraft ? for operational, safety or security reasons.

We look forward to welcoming you onboard.