Is the existing visualization already using an Excel data source? If so, you can just go into that datasource, click on the Settings tab and then reselect your updated datasheet. 

Otherwise workbench is a good option, especially if you're going to be doing this fairly often. 

Let me know if you have any questions,

Valiant

What do you mean by altering? If your chart doesn't have any specific date paremeters or you add new data that would be included in the visualization it will change to account for the new data.

Valiant is correct about the fact that you can just reupload an excel source if it's been updated and all the visualizations will be intact but adjust for the new data. Is this not what you're looking for?