Over the last few years, the Philadelphia Museum of Art has trumpeted a major $228 million renovation, designed by the architect Frank Gehry, that is to be completed next fall.

But over the last several months, the 144-year-old institution has been forced to undergo an overhaul of a very different kind.

Complaints that a manager, Joshua Helmer, had made advances toward multiple female employees during his tenure and that museum officials failed to respond to the women appropriately, have led to weeks of reckoning between the institution and its staff.

Mr. Helmer’s quiet resignation in 2018 seems to have done little to quell staff frustration. Since the complaints against him surfaced publicly in January, more than 400 current and former staff members have signed a letter calling for greater accountability and structural change at the museum. Some come to work each day wearing “We Believe Women” buttons.