# data[].attributes.body
Direct changeover is likely to be the most appropriate. It is where the use of the old system stops and the new one begins. There is a cut-off point when the old system stops working.

The advantage is that it is fast, efficient, requires the minimum duplication of work, only one system needs supporting and no interfaces between old and new systems are needed.

The disadvantages are that if the new system fails to work, there will be disruption. The new system has to be completely implemented during a period of time when the system is not required and there may be some disruption to customers while staff get used to the new system.

# data[].attributes.body
In a parallel changeover, the old system  and the new are run side by side for a determined period of time.

The advantage is that if there is something wrong with the new system, the old system is still in operation and can continue to work. The disruption to the customers is minimise and the results from the old system can be compared with the results from the new. This will establish trust and confidence in the new system.

# data[].attributes.body
Phased changeover is used with larger systems where the system to be put in place has several smaller subsystems. Each subsystem is introduced one at a time, making sure that each one is working before you begin with the next. The actual installation method can be direct or parallel.

The advantages are that each subsystem can be introduced with a minimum of disruption and if a system fails to work, the system is small enough to correct the errors.

The disadvantages are that the changeover may take a long period of time and create an extended period of unsettlement.

# data[].attributes.body
Pilot changeover is used in large organisations and involves the new system being tested in a small portion of the organisation for a determined period of time.

The advantages are that bugs can be worked out with the minimum of disruption, and training and testing can be completed in a small section of the organisation.

The disadvantage is that several changeovers need to take place.

For example, a retail chain could implement the new system in one of its shops. When confidence in the new system is high, the rest of the shops can begin to use the new system.