Change request: Change request is a formal proposal for an alteration to some product or system. In project management, change request often arises when the clients wants an addition or alteration to the agreed upon deliverable for the project. Such a change may involve an additional feature or customization or an extension of service, among other things. Because change request are beyond the scope of the agreement, they generally mean that will the client have to pay for the extra resources required to satisfy them.
Change request can also originate internally. Internal change request can involve a wide variety of actions including patching software and hardware updates.
Once a change request has been made, the process of change control should be undertaken to make sure that the request is satisfied efficiently and without unnecessary use of resources.
Service Request:
Service requests are that request coming from a user to service desk (or in some cases, self-help channels) and fulfilled through request fulfillment. Change request are requests for modifications required in any part of services, Service management system or underlying system and components.
Service request can include request for some changes that a user “is entitled to ask for” – often defined as those forming part of standard request from users. To fulfill those service request (those who involving changes – not all), applicable change management process (or change model) need to be followed. In fact, In the fulfillment of service request, two or more process might work together – along with the request of fulfillment there could be processes such as a change management, release management (where applicable), access management etc. This is very much like for resolving an incident (or problem) – you might need to change and hence has to follow change management process.