a) You save the old workbook with new name. Now you have a new workbook where all formulas refer to ranges in new workbook. After that you can make any changes, delete abundant data, add new data, edit existing data, etc.

b) You create a new workbook and copy table headers and column widths from old workbook sheets into new workbook sheets (use PasteSpecial > Values and PasteSpecial > ColumnWidths). Then copy header and 1st data row from every table on old workbook, and use PasteSpecial>Formats to paste formats into according tables in new workbook.
After that you have to select a field with formula in it, copy the formula in formula bar field, and copy it to according field on new workbook. Repeat this process for every formula field in top rows of old workbook tables. Or you copy a top row from every old workbook table and use PasteSpecial > Formulas to paste it to new table, then clear all cells without formulas, and edit all cells with formulas removing references to old workbook with references to new workbook (usually you can use ReplaceAll to do this).
Now you can copy every table down for as much rows as you need, and enter your data into fields without formula (manually, or copy)