回复：回复：Different cases are somewhat diffeent.

谢谢回复。是绿卡女儿申请妈妈。老人今年2月份凭B2签证来美，应该是8月到期，希望是能再申请到延期，如何准备材料，请指教，谢谢！

-Checklist:

1. Completed Form I-539

see:

http://www.uscis.gov/portal/site/uscis/menuitem.5af9bb95919f35e66f614176543f6d1a/?vgnextoid=94d12c1a6855d010VgnVCM10000048f3d6a1RCRD

2. Check of $290 for filing fee

3. Original I-94 (keep the photocpoy in your record).

4. A letter explaining reasons for extension

5. Proof of financial support for the period requested

6. Any other documents required by I-539 such as copy of passport, etc. (See I-539 Instructions).

Also, keep the copies of all the documents you send for the application until the extension application is approved.