Ms McKinnon works for Moore Law and is involved with a number of charitable trusts. She is chair of the Powerco Whanganui Trust and of the Rotary New Zealand Board.
She said she was aware of the challenges the DHB faces. "Here in Wanganui we have a good system but serious health challenges - the WDHB covers a large geographical area with a decreasing population, and that means less funding.
"We're also a low socio-economic population with a lot of elderly people, and they traditionally have high health needs. Our challenge is to make our dollars go as far as they can."
Ms Joblin was disappointed to no longer be leading the board, but was confident it had the "strength and resilience" to forge a solid future for Wanganui health services.
"It has been a privilege to serve as chair of Whanganui District Health Board which I have watched go from strength to strength as our board, staff and community have addressed and overcome many hurdles."
Ms Joblin offered her support to Ms McKinnon.
"I am sure Dot's strong commitment to Wanganui will augur well for our board and community."
Whanganui MP Chester Borrows paid tribute to Ms Joblin for her "invaluable contribution".
"She took on the chair during particularly difficult times and she has turned that around, and leaves the WDHB as one of the country's best performing boards."
The DHB has seven elected members and four appointed members. The elected members were decided at the last local government elections in October, while the remaining three appointed members will be announced next week.