"That was it," said White, 79. "We were out on our own."
This week the school they founded in that room above what is Narberth's only movie theater is celebrating its 40th anniversary.
The Pennsylvania Academy of Ballet, now in studios down the street from the movie house, has taught thousands of students in its decades on Narberth Avenue.
More than 70 of those students have gone on to become members of professional companies, including the San Francisco Ballet, American Ballet Theatre, and the Pennsylvania Ballet.
Several of those former students will return Wednesday to perform in the company's anniversary celebration at 7:30 p.m. at Lower Merion High School.
Missing from the audience will be the woman whose hand de Saá couldn't seem to let go of last week, as the two women watched a rehearsal for the performance.
De Saá's identical twin, Ramona, director of the National Ballet School of Cuba, was visiting the United States for the first time since the sisters were torn apart by the revolution and its aftermath.
In 1964, Margarita - married to White, who is originally from California - decided to leave. Ramona, married to a close associate of Castro, stayed. The sisters' story was chronicled in the 2004 PBS documentary Mirror Dance.
Sitting in the reception area outside the academy's main studio space, the sisters sat side by side, simultaneously declining to give their ages.
"I never thought this was going to happen. This is very emotional," Ramona de Saá, speaking in Spanish, said of the visit with her sister, who translated for her.
Ramona de Saá's trip was part of a monthlong U.S. stay that included teaching at a ballet school in Sarasota, Fla. Ramona de Saá was to return to Cuba on Sunday, before the anniversary performance, but not before seeing what her sister has accomplished in the years since they were separated.
The Pennsylvania Academy of Ballet has thrived as part of a landscape of dance schools that includes other similar preprofessional conservatories and recreational dance schools for children.
"For a suburban school to produce 70 professional dancers says a lot about the quality of the training they are receiving," said Amy Brandt, editor of Pointe magazine and a former member of the Suzanne Farrell Ballet.
Last year, White and de Saá began turning over the reins of the school to their daughter, Melinda White Pendleton, a former professional dancer who trained at her parents' school.
She will soon be in charge of managing the school where about 250 students - from ages 5 to 90 - take classes each year. Pendleton's parents are in the process of retiring.
White and de Saá married in 1960 after meeting in Los Angeles. Margarita and Ramona de Saá were dancers with the Alicia Alonso Ballet Company, of Cuba, which was performing in the city. Later, White was contracted to dance with the company and moved to Cuba.
After the revolution, the Alonso company became the National Ballet of Cuba and was infused with government support. But by 1964, the island's disintegrating relationship with the United States - marked by the Bay of Pigs invasion, the Cuban Missile Crisis, and the severing of diplomatic ties - prompted White and Margarita de Saá to leave.
"It was very hard in the beginning," said Margarita de Saá, who kept her plans a secret from her sister, a supporter of the revolution.
The Whites eventually settled in the area and began teaching at the School of the Pennsylvania Ballet. They proposed starting a suburban branch. The plan was initially approved, but when financing fell through, the couple decided to go out on their own.
"We got a map and started driving around," John White said. "We happened to stop in front of the theater, and looked up."
Through many years of the dance school's growth, the de Saá sisters remained estranged, but eventually reconciled and began seeing each other outside of Cuba. Margarita's first return to the island was chronicled in the 2004 documentary. Ten years later, it was Ramona's turn to visit. In Cuba, she directs an expansive program in a state-of-the-art facility that trains 3,000 dancers a year.
"Beautiful," Ramona de Saá said, describing her sister's school. But "they need a bigger space."
The academy's small brick storefront headquarters has been a training ground for Pamela Kubiak, of Narberth, since she was 5.
Kubiak, now 22, dances with the Manassas Ballet Theatre, in Virginia.
"The art of classical ballet is really special, and they showed me that," said Kubiak, who will be dancing at the anniversary celebration. For her, the academy's instruction has changed ballet "from an activity to a passion."
When Kubiak signed with the Manassas company, it was her turn to participate in an academy ritual. Graduates who join professional troupes sign the wall outside the main studio. Kubiak's signature is in red.
Last week, John White sat in front of the expanse of multicolored autographs and talked about what he wants for the school's future.
He pointed to the signatures and said "more of these," and what they represent.