I already filed for 2019. I wrote that my parents can claim me as a dependent, how can I change this? Do I need to amend?

[msgdds]

I (Michael Goodman) already filed for 2019 on behalf of Stella Vallon (my granddaughter),  I inadvertently did not check that she is a dependent as she resided with her mother from Jan 2019 thru July 2019 (7mosnths). Thus I now realize that her mother (Melissa Vallon) can claim her as a dependent. She is a student at Temple University and turned 18 on July 27, 2019. Please advise on what should be done to clarify my error.  Stella's mother would like to file her taxed with Stella as a dependent.  What steps do I need to take to correct my error. 

[MayaD]

If you already filed your return, you need to amend to make any changes. 

Did your parents file their return?

Do you qualify as a dependent on their return?