Will that be hard, soft or factory, sir? If you need to reset the password and/or settings on an Airport Express base station — brilliant device — then there are three methods available to you and which one you choose depends on what you need to do.
Before beginning any of this, make sure Airport Utility is up-to-date as it’s necessary to reconfigure after applying two of the three reset methods listed:
• Open AirPort Utility in Applications > Utilities.
• Select AirPort Utility > Check for Updates…
• Install the most recent firmware and version of AirPort Utility available for your Mac.
Before you attempt any of these reset methods, plug in your Airport Express (do not plug in the ethernet, USB or audio cabling) and let it go through its start up process, because the first two methods won’t work until the unit is fully up and running (blinking amber light).
Soft reset — Gives you five minutes to change the password or other discreet settings.
• Press and hold the reset button with a pen or pencil for one full second. The light (LED) will flash (blink rapidly) amber, indicating that the AirPort Express is in soft reset mode
Hard reset — Erases all user settings on the AirPort Base Station or Time Capsule but retains saved profiles. Gives you a quick n’ easy to to rename and repassword your device.
• To perform a hard reset, press and hold the reset button with a pen or pencil for 10 full seconds (flashing amber when it’s reset).
• Release the button. The AirPort Express will hard reset.
Factory default reset — The same as a hard reset but also removes any saved profiles. So, you wanna get rid of everything (i.e. you bought a used unit)? This is the way.
• Disconnect the AirPort Express from power
• Press and hold the reset button with a pen or pencil, then plug the AirPort Express back in while continuing to hold the button until you see the light flash rapidly. This should happen after a few seconds
• Release the button. The AirPort Express will factory default reset
Now, fire up Airport Utility, select your device and go to work. Airport Utility is super easy to use, though there is a full user manual (.pdf) should you need it.