change code?

You need to use your existing code to change to a new code. You do not say what alarm system/model you are using. If you do not have an existing code, then you may out of luck.

Some systems allow a reset at the control pannel, but may also be 'locked' with an engineers code.
Some pannels can be fully reset at the pannel and this will revert back to default settings.

Guy
January 2009