If you don't want to the lock capability just hide that feature for all authors so you don't have to deal with so much customization on the back-end. Hiding this feature would be better and authors would not confuse why the page gets replicated even though the page was locked.
Depends on the AEM version, you may be able to hide this using jus the permissions or you'll have to overlay the OOTB JSP's to hide this lock button.
@Kundan_Ray1 if I understood your case, you are using lock feature that if any author makes change to page and want to publish the change later and also restrict any other user not to make any other changes on same...
This feature is OOTB supported by Publish later feature by way versioning... where when author makes it Scheduled Publish.. it will create a version of current state of page and publish that version at the scheduled time..
@Kundan_Ray1 Thank you for reaching the Adobe Experience League community. The first case, why do you want to replicate a Locked Page? It was there for a reason. Author's may do changes on the page, but before they finalize and make it ready to publish, they may lock the page. If you enable replicate the page even on Lock, will unintentional changes goto Live Site?
Please explain a bit more about your usecase so that, we can suggest you better for the initial problem.