If you have a working key of the same type (door, trunk (boot), etc) simply take it to anyplace that makes keys and they can copy it. If you do not, you will need to take your title (proof of ownership) to any locksmith who can make a key from the VIN number / or the dealer who can do the same thing.
A dealership would be able to replace the key.
How do you replace a key battery on a 2004 Saab 93
Broken Key
There is no battery inside the key to replace. The key actually charges through your ignition. If its not functioning you will just have to order a programmed key from the dealership.
what does replace means
According to my owner's manual you must contact a BMW dealer to replace the key.
To replace a broken key in a 91 Subaru ignition, you will need to contact a locksmith. The locksmith can cut a key to match your ignition.
When the keyboard is in the "insert" mode, any key that is struck will replace whatever character was at that point.
how do i replace a trunk lock with another lock that has a key
You do not need a key to replace the ignition switch.
at the dealer
To replace a bike master U-lock key, first locate the lock’s key code, usually found on the lock itself or in the original packaging. Contact the manufacturer or authorized locksmith with the key code to request a replacement key. If the key code is unavailable, you may need to replace the entire lock. Always keep a record of your key code in a safe place for future reference.