Perhaps the third time will be the charm.

At an awards ceremony taking place 52 stories above the World Trade Center site, the architect of the Freedom Tower today will present recent design changes in front of more than 700 members of New York’s architecture and design community. David Childs of Skidmore, Owings & Merrill could be trying to restore some enthusiasm for the centerpiece of ground zero.

The 1,776-foot-tall Freedom Tower has been termed the commercial “white elephant” of ground zero by critics who doubt that the building will be able to attract many private sector tenants, considering its potential as a terrorist target and its relative distance from public transportation. Following lengthy negotiations between the state, the city, the Port Authority, and developer Larry Silverstein, construction on the Freedom Tower began in earnest in late April.

Security requirements of the New York Police Department sent Mr. Childs and a team of architects back to the drawing board last spring to ensure the tower would be protected from truck bombs on nearby West Street.

The second round of designs, which included a 200-foot fortified steel base and a more conventionally shaped tower, received mixed reviews. One critic called the designs “somber, oppressive, and clumsily conceived.” The architects wound up back at the drawing board again.

According to Mr. Childs’s publicists, the architect today will “provide a much greater level of detail with regard to critical design elements, including the prismatic glass cladding for the tower’s reinforced base, the antenna at the top,” along with “the white glass curtain wall and the generous allotment of open spaces and landscaping for public use.”

A fellow at the Fiscal Policy Institute, David Dyssegaard Kallick, said the seemingly endless series of redesigns creates uncertainty about the tower’s future.

“Is it real or isn’t it? There is some speculation about whether the next governor will want to go ahead with the plan as it is now configured,” Mr. Kallick said.

Mr. Childs and Skidmore, Owings & Merrill will receive an award today from the New York Chapter of the American Institute of Architects for 7 World Trade Center, the only office building destroyed on September 11, 2001, that has been rebuilt. That building has received widespread critical acclaim.

In the last round of negotiations over development at ground zero, control over leasing the Freedom Tower was transferred to the Port Authority, which owns the 16-acre site of the former World Trade Center, from Silverstein Properties. The latter will still oversee the construction of the tower, expected to cost $1.7 billion.

Because of the Freedom Tower’s symbolic value, Governor Pataki has been its biggest champion. He recently guaranteed that the state would persuade the federal government to occupy 1 million square feet of the Freedom Tower as a way to limit the risk to the Port Authority in taking control of the building.

The Port Authority chairman, Anthony Coscia, said this month that further changes to the Freedom Tower could be necessary if Mr. Pataki fails to secure the government tenants by late September. Port Authority officials have suggested that those changes could include lowering the height of the tower.