@Dillibabu77 Changes you apply to the same branch to test things on DEV will not affect the currently running production pipeline. When a pipeline kicks off, code checkout happens right after the Validation step and at the start of Build & Unit Testing and generates the code artifacts at the end of the phase. Generated code artifacts in the Build phase will be deployed to Stage and Production environments.
However, if you're making non-release changes, probably it's a good idea to create a separate branch out of the release branch and select the new branch in the non-production pipeline to deploy it to DEV.