Why it matters: With elections just months away, the lack of detailed planning raises questions about whether the new mayor will be ready to take on responsibility for policing two counties from day one.
The details: Under Government plans, both counties will elect a new regional mayor in May next year, who will be given greater powers over transport, adult education and skills, and housing. But Mr Passmore said this amounted to just a "rough idea" of what was bound to be a major reform, less than a year from election day.
He was formally told recently that his role, alongside that of Norfolk and Essex PCCs, would cease to exist from April 2027, with powers transferred to the new mayor – a role which he is also running for.
What he's saying: "There's an awful lot there that is not decided, and I do think the Government needs to be much clearer on exactly how this will work," Mr Passmore said.
"We can't afford for policing not to be supported, we don't want to jeopardise any of this work because of governance changing."
The risks: With a police merger not on the cards for Norfolk and Suffolk, the change comes with risks, he says, as the new mayor will need to handle two different forces, each with its own plans, Council Tax and budgets.
Lack of clarity and detail could lead, for instance, to uncertainty around charity projects, planned or ongoing, and ultimately impact on vulnerable people.
"We do not need to focus on these really important initiatives to be diluted or removed because we're looking at other forms of governance," he said.
"We cannot afford to jeopardise that, and many other things we're doing, because of a distraction and change in governance — the work has got to go on."
The opportunity: But voting in a new mayor could also bring with it plenty of opportunities, particularly around funding across Norfolk and Suffolk, which Mr Passmore has long criticised as a "complete injustice and unfairness in the system".
"The last Government didn't complete the work, and this Government seems completely hellbent on ignoring it as well, which is not good enough for people of both counties," he said.
"It is so distorted in favour of larger metropolitan areas, and it's not reasonable; those of us who live in rural counties pay our dues like anybody else."
His vision: Mr Passmore was the first public figure to announce his interest in becoming the new combined mayor as a candidate for the Conservatives in March, having represented the party as PCC since 2012 and being re-elected for a fourth consecutive time last May.
He said he felt he had the right attitude, skills and approach to ensure the transition was done smoothly and delivered on expectations.
Though a list of priorities would be in consultation, Mr Passmore said he would focus on long-term planning for water availability for farmers, encourage development to ease younger people into the housing ladder and improve connectivity between rural areas.
What's next: The Conservative vote is currently underway, with results expected soon on which candidate will represent the party.
The bottom line: According to Passmore, devolution offers a "golden opportunity" for Norfolk and Suffolk to work together, but the Government must provide clearer details to avoid jeopardising vital services and community work.
