Originally, the president's wife planned to speak to a joint commencement for students from the five high schools in the city, where 60 years ago the Supreme Court overturned laws that segregated black and white students in the landmark Brown v. Board of Education case.
But students raised concerns when they found out they would only be allowed to invite six family members to the ceremony because of space limitations. An online petition asking the school board to change the event attracted more than 2,500 signatures.
The first lady's office announced the change in schedule on Thursday.
She will instead address the students a day earlier, on May 16, at a joint event called "Senior Recognition Day," an accommodation that will allow all the schools to hold individual graduation ceremonies the following day with no restrictions on the number of guests.
"Once we learned about the concerns of some students, we were eager to find a solution that enabled all of the students and their families to celebrate the special day," said Maria Cristina Gonzalez Noguera, a spokeswoman for the first lady.