Changing a person from having actor credits to actress credits

Leslie Lyon nm0528949 had actor credits, although the character names were for female characters. Her Gender Identity field in IMDB is Female even though she had only actor credits. Someone may have assumed that the spelling Leslie (as opposed to the female Lesley) implied a male actor. But Leslie Ash (female) also has the male spelling of her name. I went through for each title, changing the cast list entry from Actor to Actress. But those entries which have been processed have disappeared altogether, both from her filmography and from the title. Is there another way I should have processed this change?