I filed the I-130 form for my husband by my Green Card. I need to change my citizenship status because I am a citizen now. What documents should I need to sent to the USCIS for that change? Do I need to fild any form for that? and Should I need to write a letter to the USCIS? If yes, what are the contents of the letter that I need to write it down? Can anyone give me an example? Thank you.