I was just reading this on the USCIS website ( http://www.uscis.gov/files/article/A1.pdf ) and saw this paragraph and began wondering:

What if I filed a petition for a relative when I was a
permanent resident, but I am now a U.S. citizen?
If you become a U.S. citizen while your relative is waiting for a visa,
you can upgrade your relative's visa classification by upgrading your
petition. Husbands/wives and unmarried children under age 21 of
U.S. citizens have visas immediately available to them.
• If you become a U.S. citizen after your petition is already
approved and sent to the State Department, you should notify
the NVC that you have become a U.S. citizen by sending a copy
of your naturalization certificate to the NVC. Please include a
letter with information regarding your relative and a copy of the
petition approval.
• If you become a U.S. citizen and your relative's petition has
not yet been approved by USCIS, check our website or call
customer service for information.


Under what circumstances could you Petition for a relative while being a LPR? I thught you couldn't petition for relatives while being a LPR? Just wondering if I am not understanding something.

Never mind. I got my answer.

If you are a lawful permanent resident, you may petition for a green card for the following relatives:

Husband or wife;
Unmarried children