Blue becomes events director for the company's European events portfolio, organising events for the licensing, pharmaceutical and science sectors.
She will direct the Branding and Licensing show at Earls Court 2 in October.
International Confex is currently interviewing candidates to replace Blue.
"Jessica leaves Confex in a healthy position and with a strong brand," said CMPi group director Ben Greenish. "While total visitor numbers at this year's show were down by just less than 4%, the numbers of corporate visitors and conference organisers were up, which is exactly what the show's exhibitors told us they wanted."