An auto locksmith can also rekey your ignition. Rekeying is the process of changing the internal components of a lock so that it works with a new key. There are a couple reasons that this may be needed or requested by the customer. The first is that it may be easier than replacing the ignition cylinder altogether. This is rare, but it can happen. More likely, ignition rekeying is carried out by an auto locksmith so that the customer will not need two keys to operate their vehicle. The reason that a car owner would need two keys is that a replacement ignition is not going to be keyed alike to their broken one. New ignitions come pre-coded with a few new keys.
As the locks on your doors and the trunk are not being replaced, these locks will still only work with the old key. That means if you would like to open up an exterior lock on the vehicle, you would need to have a different key. As these keys can often look identical, it is easier to just use one key. The option you have after deciding to rekey the lock is that you can rekey all of your exterior locks or just your ignition. Rekeying the ignition is quicker and cheaper than servicing all of the car locks, but either is possible.