Two letter words can be hard to search for can't they.

Here are a couple of past threads on the topic:

http://www.flyertalk.com/forum/marri...-customer.html
http://www.flyertalk.com/forum/marri...2-what-p6.html
http://www.flyertalk.com/forum/marri...s-p6-mean.html
http://www.flyertalk.com/forum/marri...der-check.html
http://www.flyertalk.com/forum/marri...now-about.html
http://www.flyertalk.com/forum/marri...-premiers.html

And there are more believe it or not. BTW, I did a search using the term " P6 ". (Note the space on either side of the P6, that is the key for this type of a search.)