Impact analysis done by PM and his team.
(it is a very important step before Approval/Reject)
("Change request approval by project manager" is defined in the change management plan then he can do approval/reject)
An authority within the project management team or external organization.
(is it a definition or near by for CCB- Change Control Board Commitee) who is responsible
Well, according with PMBOK, it should be indicated on the Project Management Plan, where is stablished how is the change management approached.As Kiron Says, it should be indicated on the Change Management Plan. In my experience, most of changes are approved by sponsors, but again, you should check your PM Plan or CM plan. Saving Changes...
Never. The only responsability from project management perspective is to manage all activities defined inside the project change mangement process to create de needed information to put it on hands of people that must decide about the change. Saving Changes...
Typically in IT Software Change management process is handled and managed by Project Manager and never approved by PM. There will be board or panel consisting of mostly senior management and Business Lead/team who would approve or deny the Change request. Saving Changes...