My Ancestors Named Frazier Also Spelled Their Name Fraiser

On some records, such as the Ohio civil war record and Warrensburg, Mo, burial record for William "S" Fraiser, born around 1832 or earlier, was spelled differently than subsequent generations, who spelled the name "frazier." If anybody has ever head of William and Maggie Fraiser, born 1830's and moved to Brunswick, Chariton Mo by 1880, Sarah Pratt Frazier and husband David of Iowa, Edward and Ada Frazier of Oklahoma, Kansas and Missouri, or Frank Beaumont Frazier of Missouri, Oklahoma, Kansas and Texas, please post a response. Thanks, Cathy