H.R. 3556 modifies how the Small Business Administration handles disaster assistance applications for small businesses affected by major disasters. The bill extends communication deadlines to 60 days after application deadlines and allows the SBA to accept late applications if applicants can demonstrate good cause for missing the deadline. Additionally, the legislation requires the SBA to notify not only congressional committees but also the individual offices of members of Congress representing affected disaster areas about application deadlines and program information. The bill affects small business owners seeking disaster relief loans and aims to improve access to assistance by providing more flexibility and better communication from federal agencies.