src/Http/Message.php
public function withoutHeader($name)
    {
        $instance = clone $this;

        if ($this->hasHeader($name)) {
            $static = clone $this;

            unset($static->headers[$name]);

            $instance = $static;
        }

        return $instance;
    }
public function withoutHeader($name)
    {
        $instance = clone $this;

        if ($this->hasHeader($name)) {
            $static = clone $this;

            unset($static->headers[$name]);

            $instance = $static;
        }

        return $instance;
    }
Returns an instance without the specified header.

@param  string $name
@return static