How to restore a procedure or packages with whatever we have modified as of yesterday..whereas I dont need of current change in procedure or packages as of todays date. Will it possible to restore based on time ??pls advise me

In general no. When compiling code in database the old code is lost. At least to my knowledge.

Unless you have an versioning file system and saved the file yesterday.

I am not sure if database flashback restores packages but it would have to be enabled before hand.

Regards
Stian

If your flashback is large enough you can query the user_source view in the flashback.

In user view, only existing procedure is there...How can i retrieve old scripts??

I think you would need FLASHBACK ANY TABLE privilege to see a flashback view of data in another schema - in this case SYS, which owns obj$, source$ etc. Alternatively connect as the SYS user, although most sites understandably won't let you do that unless you're a DBA. Then you could try calling DBMS_FLASHBACK.ENABLE_AT_TIME(). (Untested as I'm not near a system where I have privileges right now.)