Regular office hours for both 71st Street and 91st Street brownstones are Monday through Friday from 9:00 AM to 5:00 PM, and Saturdays at 91st Street from 8:30 AM to 5:00 PM. Each person who enters Prep’s work locations must fill out Prep’s COVID-19 self-certification form before entering the building. Contract tracing protocols are in place, and masks are required to be worn in all common spaces. Unfortunately, with very few exceptions, outside guests will not be allowed into the buildings. Thank you for your understanding.