Cory, who has been at Frank since 2005, has not yet set a date when she will join Citizen Relations.
The agency network comprises the newly formed Citizen Brando in the UK, following the merger of Band & Brown Communications and Brando, and partners across North America, Asia-Pacific, India and South America.
These include Citizen Paine (USA), Citizen Optimum (Canada) and Citizen Jeffrey (South America). The network is owned by EDC.
There is speculation that Cory will also be taking an additional leading UK role at Citizen Brando.
EDC Europe president Gregor Angus said: ‘As EDC moves into its next chapter, we're delighted to be welcoming Frankie to the role of vice-chairman of Citizen Relations.
‘Her passion, expertise and experience mean that she will be integral to developing our international digital footprint and help clients negotiate the newly networked world, through the Citizen Relations offering.'
Cory formerly worked at Cohn & Wolfe, where she was creative director.