Hello PHIL528,
Re-attaching keys on notebook keyboards can be very tricky and it is likely you will have a problem attaching it back on the keyboard because of the way the keys are mounted. If you break the key or the mount under the key you would need to have the keyboard replaced. Separate keys are not available to send to users.
There are other user talking about this in the Community, but Acer does not give support for re-attaching keys.