So it will be just a different server but the same tables will be under the same schemas/databases.
In this case you should not have problems. Please follow these steps
- Rename/ remove the old connection you used when the diagram has been created.
- Open the diagram.
- You will be asked what connection to use.
- Point to a new connection.
If the tables are there the diagram will pick them up and show. But the tables have to be under the same schema/database otherwise the diagram will not know where to look for the table