If you really want to take over cinni and he is not willing to do so you can do it anyway
The only thing you really need is the community behind you

1. gather the community
2. create a new thread
3. fork the cinnicoin repository
4. contact exchanges
5. proceed cinnicoin development with your new team

it would be easier if cinnicoindev agrees to hand over the thread and github repo but since it is all open source there are ways around that