The answer to 'how to replace ceiling fan installation' is to safely remove the old ceiling fan and install a new one. First, turn off the power to the ceiling fan at the circuit breaker. Next, remove the old fan by unscrewing the mounting bracket from the electrical box in the ceiling. Disconnect the wires, making sure to label them so you can properly reconnect the new fan. Install the new mounting bracket and secure it to the electrical box. Then, connect the wires according to the manufacturer's instructions, usually matching colors like black to black, white to white, and green or bare copper to green or bare copper. Finish by attaching the fan blades and any other components, and turn the power back on to test the new installation.
It's important to follow all safety precautions when working with electrical components. If you're not comfortable performing this task, it's best to hire a licensed electrician to ensure the work is done properly and safely.