system/HTTP/Response.php
public function deleteCookie(string $name = '', string $domain = '', string $path = '/', string $prefix = '')
	{
		if (empty($name))
		{
			return $this;
		}

		if ($prefix === '' && $this->cookiePrefix !== '')
		{
			$prefix = $this->cookiePrefix;
		}

		$name = $prefix . $name;

		foreach ($this->cookies as &$cookie)
		{
			if ($cookie['name'] === $name)
			{
				if (! empty($domain) && $cookie['domain'] !== $domain)
				{
					continue;
				}
				if (! empty($path) && $cookie['path'] !== $path)
				{
					continue;
				}
				$cookie['value']   = '';
				$cookie['expires'] = '';

				break;
			}
		}

		return $this;
	}
public function deleteCookie(string $name = '', string $domain = '', string $path = '/', string $prefix = '')
	{
		if (empty($name))
		{
			return $this;
		}

		if ($prefix === '' && $this->cookiePrefix !== '')
		{
			$prefix = $this->cookiePrefix;
		}

		$name = $prefix . $name;

		foreach ($this->cookies as &$cookie)
		{
			if ($cookie['name'] === $name)
			{
				if (! empty($domain) && $cookie['domain'] !== $domain)
				{
					continue;
				}
				if (! empty($path) && $cookie['path'] !== $path)
				{
					continue;
				}
				$cookie['value']   = '';
				$cookie['expires'] = '';

				break;
			}
		}

		return $this;
	}
Sets a cookie to be deleted when the response is sent.

@param string $name
@param string $domain
@param string $path
@param string $prefix

@return $this