Cowdry, who joined from O2 in 2013, is expected to leave the business amid a "regime change" at the National Lottery operator, according to a source familiar with the matter.
She was hired and reported to then managing director Duncan, who stepped down as chief executive last month after six years at the company.
A replacement for Cowdry is likely to be announced very soon, Campaign understands.
A Camelot spokesman said: "We would like to thank Sally for her contributions to Camelot and The National Lottery over the last four years."