Update a list rather than just add to

[Kiwi den]

I have a spreadsheet that I want to use to list data from 2 other spreadsheets.I want to update the data on my new spreadsheet rather than adding it as a list. ie new sheet Data from XL1 and data from XL2 If these files are altered or added to then I would like the new data to overwrite any changes or add if new. Your thoughts would be greatfully appreciated