Why there are 6 different ways of introducing a change?

As per the change management webinar, there are n ways of initiating a change and they are as follows:

Raising an Issue - CR-CO-CA

Raising a CR-CO-CA

Raising a CO-CA

Raising CA

Raising Issue -CO-CA

Raising Issue-CA


Why are all these 6 methods introduced? What was the necessity behind introducing all these 6 different ways of introducing the changes?