A retail developer is buying a portion of the old Macy's building in downtown St. Paul with plans to use it for a new store, the building's owner said Friday.

The St. Paul Port Authority, which bought the building after Macy's left, signed a sale agreement with developer NLD Wabasha, a Delaware limited-liability company with ties to Minneapolis-based ­Capital Real Estate, for two floors totaling 25,570 square feet that will be transformed into an undisclosed national retail concept.

The sale price is more than $2.5 million, with the bulk of it due at closing, according to a memo sent Friday afternoon to the Port Authority's board members.

"These folks wanted to own a chunk of the building, which excited us because it means a long-term ­resident," said SPPA President Louis Jambois. "It's a quality developer working with a quality retailer."

NLD Wabasha is nabbing what is arguably one of the best portions of the 363,000-square-foot building. The retailer it has lined up will fill 17,870 square feet on the Wabasha Street level and 7,700 square feet on the skyway level on the block's southwest corner. But it won't take up all the available street- and skyway-level retail space.

"Our expectation is that the street level of Wabasha will still have at least two to three storefronts opening right onto the street," said Lee Krueger, the Port Authority's senior vice president of real estate and development.

Several restaurant owners have expressed interest in having sidewalk dining on the site, he said.

"But no one really wanted to be the pioneer and go in first. That's why we are so excited about this because so many people have said, 'If you get something, we are really interested in joining,' " Krueger said.

As for the building's remaining space, its fate remains unclear. The Macy's store locked its doors more than two years ago, and it's been more than a year since the Port Authority purchased the 2.25-acre site for $3 million.

"Originally, we thought it might be a demolition and new construction project when we bought it, but we basically got no interest in that. But we were surprised by how much interest we received in a retrofit of the property," Jambois said.

"The building is built like a bunker. It's concrete, steel and more concrete" with a parking ramp, he said, and so a multiuse facility made the most sense.

The Minnesota Wild confirmed in February that they were in serious discussions with the Port Authority, a quasi-governmental entity active in the city's economic development, about a potential practice facility for the hockey team at the site.

"The Wild are a little preoccupied right now," Krueger said, referring to the NHL playoffs. "They are well aware of everything we are doing, and they've been extremely supportive of everything we are doing."

On Tuesday, the Port Authority's board of directors is expected to vote on the sale. If approved, the closing is expected in the fourth quarter.

Also, the buyer has an option to purchase an additional 2,000 square feet on the skyway level for $196,000.