There's a connect entry describing exactly my Problem:
Using the Master Data Services Excel Add-in, user establishes a connection, creates a table of data from an Entity and saves the Excel file. If in the future they want to change the Connection (e.g. point to a different MDS server), there is no apparent way to acheive this.
Did anyone found a pragmatic Workaround for switching the Connection/Server for existing MDS-Tables in Excel? This shouldn't be rocket sience or? Where does the addin store this "metainformation" within Excel-file?