While our editors are highly skilled in improving images, we can only do so much when it comes to sharpness.
Cameras capture information that is in front of them. Factors such as bad lighting, motion, or object distance can affect the cameras ability to capture details. Unfortunately, with blurry images, if the information isn't there to start with, we have no way to accurately recreate what is missing.
If important details, such as facial features aren't visible, we won't be able to restore them. If your image is only slightly blurry, we do have the ability to sharpen it a bit, but please note that it will never result in a crisp, clear, great quality image.