Extend stay beyond return date marked on passport

[Kamal100]

My mother has a 10 year multiple entry visa to USA. She came to USA on 10-MAR-2017
with a return ticket dated 19-NOV-2017. At Dulles Airport her passport was stamped
to depart on 10-SEPT-2017. What is the process to extend her visa till 19-NOV-2017

[PryncissQueen]

https://www.immihelp.com/extend-non-immigrant-stay-in-the-united-states/

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