You can use your resident Zerodha account even after going abroad if your stay is less than 6 months. If it is more, you would be considered an NRI, and you would have to convert your resident account to an NRO account. Alternatively, you can close your resident account and open a new NRI account.
When you move abroad for employment, business, or any other purpose, that indicates your intention to stay outside India for an uncertain period. In that case, you become a non-resident from the day you leave India.
It is the duty of the clients to declare their residential status.