Takeover has different meaning in different fields of industry. In general, takeover is some action in which you are moving one element with dependent attributes from one parent entity and put it on some other parent entity. The values of attributes must be the same before and after takeover.
For example, if you have some billing system with customer structure and contract structure on some customer. The contract structure can be very complex, lot of services with interdependent parameters. So, if you want to move one contract from one customer to another customer maintaining all services same, we are providing contract takeover.