How can i rollback on an update command ??
The command was issued on multiple tables without using transaction and without using commit.
Is it possible to rollback to previous state.

Nope. Sybase is by default an implicit commit system. You can set individual sessions to behave differently, but if you did not begin a transaction, you can not roll it back. To get the data back, you will need to restore the database, or regenerate it from whatever original source it came from. If that original source was manual entry, you may have a bit of typing ahead of you.