If the Certificate holder's household size, address, or income has changed,the holder must mail copies of the supporting documents to the MPDU office. Changes must be submitted in writing to the MPDU Program. (Include the Certificate number with all mailed documents). Please click on the link below for instructions about what documents to submit with the changes. Send copies of the documents to: MPDU Office Department of Housing and Community Affairs 1401 Rockville Pike, 4th Floor Rockville, MD 20852