Recreational Equipment Inc. is looking to sell its custom-made new headquarters and allow employees to work from home or other offices, the latest sign that the pandemic is driving companies to ditch central offices to raise cash. The retailer, known as REI, was poised to open the new Seattle-area headquarters this summer after creating a unique building that reflected the company’s outdoorsy image and could serve as a way to recruit new employees. The property features outdoor staircases and bridges, a courtyard of native plants, and skylights to let in sunshine and air.