The first phase, which is expected to be complete by this time next year, includes "reorienting" the interior corridors of the center's 160,000-square-foot main building, too many of which are dark and lead to dead-ends, Blancarte said. Interior renovations also will include the creation of an interior courtyard area, possibly featuring a dome, for special events. A glass elevator will be installed near that central courtyard.

Skylights featured in the early construction of Trolley Square will be uncovered and updated to add natural light and a sense of openness, Blancarte said.

The renovation on phase one likely will begin in early 2007 and will take place after hours, Bard said. All businesses are expected to remain open during the renovation period.

Phase two will focus on parking, outdoor landscaping and design, and will include the addition of underground parking and a new parking structure to replace the one at the western edge of Trolley Square. Work on the parking garage could begin as early as next spring, Blancarte said. Upwards of 120 residential condominiums also may be built atop that structure at some later date.

Designers are looking at adding fountains and fireplaces, increasing pedestrian space and public gathering places. The area between Pottery Barn and Restoration Hardware may take on the flair of a European village street, Bard said, with cobblestones and benches.

Shoppers will notice a change as early as this weekend, when Trolley will launch its first valet parking program. The center also is in the process of reorganizing its south parking lot, which it believes will add 20 percent to its parking capacity. And, Blancarte said, the western parking structure will get new paint and more light to increase utilization there.

As work progresses, Bard said designers will be looking at possible uses for the south parking area, which could include more retail or residential space.

Phase three contemplates the addition of a new retail building at the property's northeast corner, a 50,000- to 60,000-square-foot building that could occupy one or multiple tenants and includes several levels of underground parking, Blancarte said.

Phases two and three — without the residential units, which are contingent on permits, consumer interest and other factors — could be completed by 2009.

Speculation about the identity of the yet-unnamed retail tenant has ranged from Whole Foods to Crate & Barrel to Cheesecake Factory. Neither Bard nor Blake Hunt Ventures would comment Wednesday.

"Whatever tenant ultimately we think will improve the tenant mix at Trolley," Blancarte said. "It will be one that will increase the draw and excitement at Trolley Square. Whomever it may be, it will be a great retailer."