You can switch to TCP/IP mode from EtherCAT by either one of two options as below
1. Perform a factory reset. This can be done by unplugging the power supply from the AC side, and then replugging it while holding the Power button on the robot's base for about ten seconds or till LED lights on the robot base stops blinking.
2. You can set the EtherCAT Object 8000h subindex 1 to 1 using a SDO Write function