force release of usb and/or serial port and re-scan usb devices

How do I release on open serial port or force a re-scan of ports without rebooting?

After a clean reboot I can plug an FTDI usb serial device into any usb port and it will get recognized as

/dev/tty.usbserial-FTG9KGQ4

Now if I access the device as a serial port, then either the software crashes, or the software process is killed or I physically unplug the usb serial device while the serial port is open, I cannot re-connect the serial device after re-plugging it into the same usb port, and /dev/tty.usbserial-FTG9KGQ4 disappears.

I can re-connect the device only if I plug it into a different usb port or I reboot my macbook pro.

What I see is that OSX is somewhere locking the usb/serial port as busy. How do I release that serial/usb port without re-booting?