This was announced through official website.
Giselle also posted her farewell message and thanking the fans on her Twitter account.
Full official statement:
"Thank you always for your support for JKT48.
Alia Giselle from 10th generation and Aulia Asyira from 11th generation of JKT48 have submitted their resignation from JKT48, and after discussion with the relevant parties, the management decided to respect their decisions.
Therefore, as of April 3, 2023, Alia Giselle and Aulia Asyira will no longer continue their activities in JKT48.
Further information regarding the refund process and replacement of members for Personal Meet and Greet and 2-Shot sessions with the members concerned will be announced further.
Please understand and thank you."