Is there a difference between change management for scope, cost and schedule? Is the flow of the change management for all three areas the same?
Yes, the flow is the same, because you're not talking about a change to the scope, or the cost, or the schedule, you're talking about change to the project.
Change management (or control) deals with those three in that for every change, all three must be assessed for impact. "How does this change in scope affect my schedule? How does this this delay affect my cost?, etc."
So there's no separate flows or processes for each. Any and all changes need to weighed against the project as a whole for impact, and this includes three mentioned, but also for possible new risk, stakeholders interests, etc.
Your process for change management should be the same regardless of the type of impact. What will vary will be who is allowed to approve a change.
For each of scope, cost and schedule (and also risk, quality, benefits and resources) you should set tolerances up front for the production team leader, PM, project sponsor, steering committee, etc so that decision making devolves to the lowest appropriate level given the priorities, criticality and complexity of the project and corporate culture.
For example, a critical project in a cost-averse company may require steering committee approval for any increase in costs, but the same project may only need PM approval on schedule increases of less than 2 months and project sponsor approval for increases of 2 months or more.
You should still have a single gate-keeper (an individual or committee) through which all change goes through so that the changes can be communicated to stakeholders and the plan can be updated.