Determine how much time is left in your contract with ADT. If you contract has already expired, you may be on a monthly service plan, in which case you may cancel at any time. You can call ADT and speak with a customer service representative to determine the time remaining on your contract. You may still terminate your contract if it has not expired, however you may be subject to an early termination fee.
Sign a service contract with the new company and provide them with the make and model of your currently installed security system. The make and model will be located in the control panel, which looks similar to a fuse box. If the security company is able to activate the installed security system on their network, they will not need to install any additional equipment. If your current system is not compatible with their network, you will need to arrange for a technician to install a new security system, which may involve additional fees depending on their current promotions.
Cancel your ADT security plan prior to the service activation date or installation of the new security system. You can cancel with ADT by calling their customer service telephone number and speaking with a representative.