If you're only going to be gone for a few months, you can keep using your trading account because it doesn't change your status to Non-Resident Indian (NRI).

If you're going to be away for more than six months, you'll need to alter your account to an NRI account.

Let's say someone leaves India for work, business, or any other reason that shows he intends to stay outside the country for an extended period. In that situation, he ceases to be a resident of India on the day he departs.
It is the clients' responsibility to report their residency status in both circumstances. You have the option of converting your existing Trading & DEMAT account to an NRO account or closing your resident account and opening a new NRI account.