回复：关于返美证renew

If you are applying for renewal of your advance parole document (I-512L or I-512), USCIS will accept and adjudicate Form I-131 filed up to 120 days before the date your current Advance Parole document expires.

是不是我要用I-512?, 可是uscis上面没有I-512表啊？

I-512 = the approved AP, the paper document you use for the travel which has your picture, etc. information. Form I-131 is the application for the I-512 (AP). Just look at your old AP paper, and you will find it out.