yes we can change but fee not refunded. window open before 1 month to the halltcket download. this attempt may be from 7th sept. stay tune watch notificaions in icai website (and your account icaiexam.icai.org) from today onwards strictly.
Correction window 1 starts from 7th Sept 2018 at 11am till 13th Sept 2018 midnight
Over there you can make only 3 changes 1) Change in Medium in case of mistake (English to Hindi and vice versa)
2) Change in Exam Centre and Zones if applicable (only within India)
3) Change from 1 group to another or from both groups to 1 group of your choice (change from 1 group to both not accepted. Also no refund will be made)