How to configure postfix for sender address rewriting?

Issue

• How to configure postfix for sender address rewriting? For example, when the system user oracle sends an email then postfix should rewrite "oracle@hostname" to "no-reply@example.com".

• When trying to deliver mail via my ISP mail relay, I get the following error in the logs:

  553 5.7.1 <root@hostname.domainname>: Sender address rejected: not owned by user user@domain