Yes, it's possible to take admission in 11th grade after completing 12th grade, especially if you wish to change your stream or academic path. This is typically done by enrolling in a new school, or through open schooling options like NIOS.

New School Admission: You can apply to a new school for 11th grade, adhering to their admission procedures and eligibility criteria (primarily based on your 10th-grade marks). You will need a transfer certificate from your previous institution.

NIOS: The National Institute of Open Schooling (NIOS) offers a flexible way to pursue 11th and 12th grade with various subject choices and allows for re-admission to these grades after completing 12th from a traditional board.

Good luck!!