Do i need to strip off stain before re staining?

Yes, it's generally recommended to strip off the old stain before re-staining to ensure even color and adhesion. Stripping removes any existing finish that might interfere with the new stain application. However, if the old stain is in good condition and you're using a similar color, you might be able to simply sand the surface lightly instead. Always test a small area first to determine the best approach.