You don't need to re-install.
The connections in the Data Source Explorer are automatically populated from your local database catalog when a new workspace is created.
You have a few options:
1. Create a new workspace
2. Export the connections from a new workspace and replace them in your current workspace
3. If you shell share with ODA, ODS or IDA, use the connection configurations, in a database or configuration repository.
1. Note that other data saved in your workspace (projects, default view locations, default perspective, etc.) would have to be exported and imported, or reset for the new workspace. See:
Workspace Switching
2. Create a new workspace (as per option 1). Then export the new, updated connections, as per this Information Center topic:
Exporting and loading database connections from a database descriptor file. Then return to your original workspace, delete the existing connections and import the new, updated connections.
3. Alternately, if you shell-share with IBM Optim Database Administrator, Version 2.2, IBM Optim Development Studio, Version 2.2, or IBM InfoSphere Data Architect, Version 7.5.1, you could use the Configuration Repository. One user would update the repository with the new port numbers and all the other users could refresh their connection information from the repository. See this Information Center topic:
Managing database connections that are associated with a connection configuration