How To Write A Modified Block Letter . This format also outlines the punctuations for your reference. Modified block differs from block style in that the date, sign off, and signature lines begin at the centre point of the page line. Modified Block Letter Template Word from bestcreativetemplate.blogspot.com A subject line is not required. In this letter format, all paragraphs are indented, and the author’s address, date, and closing are usually indented in same position. A modified block style letter is a common format used when writing a business letter.