hello professionals, can we file revised return for the AY 2018-19?

No, Revised Return of Income Tax can be filed by an assessee any time before the expiry of the Relevant Assessment Year or before the completion of assessment (whichever is earlier). So, even though if your assesment may not be completed, you cannot revise your return as the relavant assessment year (2018-19) has already ended on 31st March, 2019

thank you

The basic rule is the moment the finacial year ends you are not allowed to file returns.
Say for example financial year ends for AY 18 19
ends on 31st Mar 2019

You can in extreme cases.