mistake in bank details

There are two options

1. You can revise the return by providing correct bank account details.

2. If you are not going to revise the return, first of all you should E verify the return.While Processing return you will get an Intimation saying Incorrect Bank account. Then you will get an option to Refund Reissue Request. There you have to give the correct bank account details.

the easy and simple way is to e-verify your return and revise it... or without e-verifying you can go for fresh return but it'll attract late fee u/s. 234f.

Better to revise or follow Mr JUBIN JOSE views.
No need to file fresh ITR. it's not good.

without revising the ITR, if it's processed, the refund will be blocked, after that to unblock it, higher officials permission to be obtained etc etc.. lot of complications... better revise it

No such complications . If bank account is wrong the refund failure intimation will be get to the Assessee. Based on that he can submitt Refund Reissue Request through Income Tax Portal. I had been collected the refund of so many people through this way.
No need to go for Higher Officials.

Refund Reissue Request currently not working.. only shows past generated requests.. You cannot generate new request.. may be some kind of bug there