In the new role, Canavan will continue to report to global chief executive Philippa Brown and be part of the worldwide leadership team responsible for driving the network's growth.
Canavan will oversee the strategic direction of PHD's communications and marketing activities, working closely with the leadership teams in more than 100 offices.
She joined PHD Worldwide in 2010 as global PR director before being promoted to worldwide marketing and communications director in 2013.
Over the past nine years she has been responsible for building PHD's reputation as a global media agency network, with clients including Volkswagen Group, HSBC, Singapore Airlines, SCJ and LG.
"Avril has been an instrumental part of PHD's network growth story and I couldn't be happier that she is taking on this role as we continue PHD's ambitious growth plans and make a leap in our evolution as a network," Brown said.
Canavan added: "PHD has a strong and defining heritage as a strategic and creative media agency. I consider myself privileged to work with great talent across the network to showcase the creativity, innovation and thought leadership that makes PHD stand out from other network brands. I'm looking forward to the next part of the journey."
Ozdemir was EMEA and APAC senior marketing manager at WE Communications, driving brand awareness and lead-generation activities across these regions. She is also vice-chair of the PRCA's Council.
PHD has also appointed Lisa Williams as an EMEA director in its marcoms team. She joins from The Media Foundry, where she was client services director responsible for the delivery of global campaigns in the media, marketing and technology sectors.