Sephton, 51, is leaving the business to take some time out and re-think her future career aspirations.
She will remain in the business until the end of September and continue to advise Elegant Resorts until February.
Redmond Walsh, vice-president UK and Europe of Portman Travel Group, Elegant Resorts’ parent group, “will ensure a smooth transition” by assuming day-to-day control until a permanent replacement for Sephton is appointed.
Sephton has led Elegant Resorts since 2009, after originally joining as a part-time finance assistant in 1992.
During that time, the business has grown significantly at its Chester base, where it now employs 120 staff.
Sephton said: “I’ve worked in every department of this business and am immensely proud of its success over the past two decades, but it’s simply time for me to try something new.
“The passion, attention to detail and expertise of the staff at Elegant Resorts will ensure that the company continues to grow.”
Walsh brings significant experience in the travel sector, from his time as chief operating officer at Stella Travel Group and as a former managing director for Abercrombie & Kent.
He added: “I’ve thoroughly enjoyed working with Michelle, she’s one of the best.
“She’s been at the forefront of developing client and supplier relationships, promoting the Elegant Resorts brand and leading her team with a wonderful, collaborative style.
“Michelle has made a significant contribution to the business over two decades and she will be missed by everyone. We wish her well.
“These are exciting times ahead for Elegant Resorts. We are looking at potential acquisitions in the luxury sector and are investing in our technology to improve our consumer booking channels.”
Portman Travel Group, formerly Mawasem Travel and Tourism, acquired Elegant Resorts in 2014, Clarity in 2014 and Portman Travel in 2016.