https://www.avvo.com/legal-answers/what-does-no-cos-aos-eos-mean--2059002. html "The annotation of "No COS/AOS/EOS" on the passport means no change of status, adjustment of status, or extension of status. Although it is not too common for a Customs and Border Protection (CBP) officer to include this annotation in a visitor's passport, it does happen sometimes. This annotation alone does not necessarily ban your mother from COS/AOS/EOS, or from coming back to the U.S. As long as your mother still has a valid visa, she should be able to come back to the U.S. However, that does not mean that she will be guaranteed entry to the U.S. on her next trip. It will be up to the CBP officer at the port of entry to determine whether or not your mother will be admitted to the U.S. You can apply for naturalization if you are 18 years of age or older, provided that you meet all of the requirements for naturalization. You will be allowed to petition for your mother when you get your U.S. citizenship and if you are 21 years of age or older. She will be considered an immediate relative and will be exempt from the numerical limitations imposed on immigration to the U.S. Best of luck! "