One Dalton photographed at dawn. Photo courtesy of Carpenter & Co.

With 17 condominiums lingering unsold since Boston’s One Dalton tower opened in 2019, the building’s developers are switching horses and bringing in a new brokerage to move the units.

Carpenter & Co. announced that The Collaborative Cos. will represent ownership for the remaining homes in the 61-story luxury tower, which is half-filled with a Four Seasons hotel that also powers some of the residents-only amenities.

When the building opened, Boston luxury brokerage Campion & Co. represented Carpenter for the 157 units in the building. Some of those homes fetched near-record overall sales prices and prices per square foot, but the onset of the pandemic seemed to cool sales.

“We have been consulting on this project for several months and are pleased to have formalized an agreement to manage the sales and marketing. We are collaborating with the existing sales team and brokerage community to close out this iconic development,” Sue Hawkes, managing director of Boston-based TCC, said in a statement.

TCC is fresh off pre-selling around 80 percent of the condos in Noannet Group’s Raffles Boston luxury hotel-and-homes tower elsewhere in the Back Bay, through the offices of its agent team of Cindy Dwyer and Manuel Davis.

And while the brokerage will have plenty to work with – Carpenter said that One Dalton’s remaining units range in size from 1,403 square feet to 4,152 square feet, with sweeping views, bountiful amenities and prices starting at $3.75 million – Greater Boston’s luxury market is behaving much more sluggishly than the rest of the regional housing market thanks in part to a large number of brand-new units in luxury towers.

Still, Carpenter was optimistic in a statement included in Tuesday’s announcement.

“We are thrilled to work with Sue and her team,” company President and CEO Richard Friedman said. “We have known TCC for years and have huge respect for their industry knowledge and outstanding track record.”