The phrase "act in the same manner" is correct and usable in written English.
You can use it when you want to indicate that someone should behave or respond similarly to another person or situation.
Example: "If you want to succeed in this project, you should act in the same manner as your colleagues who have already achieved great results."
Alternatives: "behave similarly" or "respond in the same way."
[1989, My emphasis.] "Genetic" exchangeability here means the ability to act in the same manner in reproduction - any two members of the species are (more or less) interchangeable.
The game was played in a good spirit, competitive and not over-zealous, and we wanted the supporters to act in the same manner.
However, this is not a realistic situation, given that not all the members in a group act in the same manner.
Any State, and any such instrumentality, officer, or employee, shall be subject to the provisions of this Act in the same manner and to the same extent as any nongovernmental entity.
Sheik Saghir, one of the Shiite clerics on the constitutional committee, said fears that Iraq's Shiites would act in the same manner Iranian Shiites did during the 1979 revolution were misplaced.
If she had that putt to win the cup, I would still like to see it". Asked if she would act in the same manner again, Pettersen replied: "Totally".
I wonder if Mr. Clinton would have acted in the same manner if he (and Al Gore and Hillary Rodham Clinton) had had to live with this during the elections.
In court filings, they suggest: "It is a striking feature of this case that Mr McKillen should be alleging impropriety in others... where he has acted in the same manner or worse.
"It is a striking feature of this case that Mr McKillen should be alleging impropriety in others … where he has acted in the same manner or worse," suggested the Barclays' counsel, Kenneth MacLean QC.
Uniformitarianism, in geology, the doctrine suggesting that Earth's geologic processes acted in the same manner and with essentially the same intensity in the past as they do in the present and that such uniformity is sufficient to account for all geologic change.
