If you are asking if you can sell your interest in the LLC to which you are a member/partner, this will most likely depend on your a number of factors; your ownership percentage, your Operating Agreement (signed by all members), any other agreements you have with your members/partners, and whether the other owners/ partners agree to your selling your interest. You may not have the ability to sell without consent from the other members/partners. If you are not sure after your investigation and discussion with your other members/partners, you should probably seek the advice of a licensed attorney in your area.
If the LLC is providing Member Certificates as proof of ownership of each members' interest in the LLC (kind of like stock certificates), there is usually some description on the back of the certificate regarding the transference of that certificate. Filing services companies like SmallBiZ.com (http://www.smallbiz.com) usually sell Member Certificates in packages of 20 certificates.
Best wishes for your LLC.
It depends on the state the LLC was filed out of, you may need to file an amendment, or send in an updated list, or just update your operating. You best bet is going to be to call the state the LLC was filed in. The phone number should be on the articles. If you don't have it, here is a link with all of the states websites http://www.myllc.com/arizona-limited-liability-company-llc.aspx