at what time I can place the After trading hours orders (ATOs) with Zerodha?
You can place orders any time from 6:30 PM to 9:15 AM (until just before market opening).
Check this link for further details -
6:30 pm to 9:15 am next morning
You can place under MIS (Intraday) or CNC/NRML (delivery/normal) product types.
You can modify your After Market Orders also, upto 9 am, next morning I guess. From 9 to 9:15, order cancellation/modification may not be possible.
Does that mean - After market hour orders cannot be modified or cancelled during market hours?
You cannot even place AMOs during market hours, Then how will you modify it?
The AMO you place yesterday will be pushed when the market opens next day, so in next day trading hours your AMO will not be alive, it would have got executed or moved to your order book as limit order.
For tomorrow, if you want AMO, you need to place from today evening 6:30 pm, Some brokers allow from 4 pm onwards. In Zerodha 6:30 pm onwards.
For CDS and MCX, after market closing time to next day market opening time, is AMO placing time.