In a brief statement, Mr. Geffen, whose gift renamed the hall for him in perpetuity, said: “I’m happy. I know they’ll do something great.”

The new approach will be less monumental and more incremental. There is not yet a price tag, a design team, a time frame, or a specific set of proposals, but Ms. Spar and Ms. Borda said they envisioned substantially reconfiguring the auditorium with work that could be done in phases. They said they would work to improve the hall’s acoustics; explore the idea of bringing the stage further into the auditorium, as the Mostly Mozart festival does in the space each summer; and weigh losing some seats to make the cavernous hall feel more intimate.

The Philharmonic has been citing an “urgent need” to renovate its home since at least 1999. In the years since, it has tapped the architect Norman Foster to create a redesign that went nowhere; made an embarrassing attempt to leave Lincoln Center altogether and return to its old home at Carnegie Hall; and wrangled for years about what it wanted, what it could afford, and how it could survive once construction started.

But the project seemed to be getting on track in recent years: Lincoln Center negotiated a $15 million deal to persuade the heirs of Avery Fisher, for whom the hall was named after an earlier renovation, to relinquish the naming rights; the hall was renamed for Mr. Geffen in recognition of his gift; and a design team was chosen. The advancing plans even became a factor in the change of music directors at the Philharmonic: Alan Gilbert said that he decided to leave after last season in part so his successor — who will be Jaap van Zweden — would have time to acclimate before construction began.

Then both organizations lost their leaders. Jed Bernstein, the president of Lincoln Center, left his post last year after failing to disclose a relationship with a staff member. Earlier this year the Philharmonic’s president, Matthew VanBesien, stepped down as well. With a leadership vacuum at a key juncture, responsibility for the project fell largely to Katherine G. Farley, the chairwoman of Lincoln Center, who had helped secure Mr. Geffen’s gift and drew on her experience in the real estate industry as she worked to guide the process.