If someone falls into the water from a dock what is the first tech thing you should do?

If someone falls into the water from a dock, the first thing you should do is call for help or alert emergency services immediately. Ensure your safety first before attempting to assist the person; do not jump in unless you're trained to do so. If it's safe, try to extend a flotation device, rope, or anything that can help them stay afloat while waiting for professional assistance. Keep an eye on the person and provide reassurance until help arrives.