Before removing the brake line check if there is a mark on your line which marks the position of the brake handle on the line. If there is no mark on the line above the knot or somewhere else please use a feltpen to mark the position of your brake handle.

In this case i added a small mark exactly on that position on the line that was hidden in the brake handle.

Slowly pull the brake line to the side that goes up to the wing to free the brake handle.

Please be carefull not to pull the line too fast, as it could get hot and damage the line coating or the brake handle.

The brake handle is now free