Lee, who leaves after Chinese New Year, will have her Hong Kong position filled by Burnett Beijing MD Kelvin Cheng. Lee has cited personal reasons for her resignation.
Lee and Cheng were rehired in early 2002, both having worked with Burnett in Hong Kong and Shanghai respectively in the late 1990s.
Meanwhile, Cheng's Beijing role will be filled by Guangzhou MD Benjamin Tsang.
Guangzhou management supervisor Michael Tsang, who has been with the agency for two years, will take over from Tsang as the office's general manager.
"We have the depth and strength of talent in our Greater China offices to manage this transition seamlessly," said Michael Wood, the network's Greater China CEO. "And it's a fantastic tribute to the team that we are able to make such moves entirely from within."
Wood said the Greater China operation had entered 2005 on a strong footing, with key wins across all four offices last year - Hang Seng in Hong Kong, Cadillac in China and McDonald's and President Foods in Taiwan.
The focus this year will be to build its marketing services offer in China as the network prepares to launch its Arc brand across the region.
"The reality is we have a significant proportion of marketing services in our brand agencies; what we are looking to do is build on these, especially our capabilities in promotions, retail and activation marketing," Wood said.
He cited the hire of ex-Grey G2/GRM Malaysia head Simon Holt as marketing services MD for Greater China as a key step in sharpening the offices' marketing offer.