In skull base surgery, robotic arms can perform endoscope-assisted procedures instead of human surgeons. However, when operating in confined spaces, avoiding collisions between the endoscope and surgical instruments presents a challenge. Conventionally, endoscopes are manipulated to revolve around a fixed Remote Center of Motion (RCM) point to prevent contact with incisions, yet this fixed approach restricts the operational workspace for surgical instruments. This paper introduces a novel method that achieves adaptive RCM point movement, allowing the robotically controlled endoscope to actively avoid surgical instruments and prevent incision damage. Simulations and experiments were conducted in scenarios with different sizes apertures. The simulation and experiment demonstrate the effectiveness of the proposed control method.