Remove workspace from Deployment Pipeline

Hi,

One of my collegue created a deployment pipeline. Now he is not part of the company. How can Power BI Administrator access the deployment pipeline created by him. If that is not possible, how can we unassign workspaces from that pipeline, so that it can be used in a new pipeline. Currently workpsaces used by my collegue is not shown while i try to assign the workspace in new deployment pipeline.

Thanks

Ebin