Thanks for the reply
I finaly got it and here are the 2 ways in full details
How to properly eject USB Stick or HD Drive connected to LG smart TV
1st way :
1- Press Home in magic remote control
2- Press the cable circle on the right of the screen ( input hub )
3- Select all inputs
4- Scroll down and locate the usb stick or hd drive under smartshare section
5- Select the desired usb device to remove
6- Press eject from the right of the screen
2nd way
1- Press and hold 123/input from the magic remote control
2- Select all inputs
3- Scroll down and locate the usb stick or hd drive under smartshare section
4- Select the desired usb device to remove
5- Press eject from the right of the screen
Regards