once a symbol is placed from the central library on a schematic, it is not possible to edit it in schematic or extract the pin info.
Thus you have to do this in central library and the symbol editor:
Edit the symbol and use file-export-pins.
save it (in this example as unnamed.tsv)
once in excel open the file and in data-convert-text to column, convert it so that every cell has a value.
now you can play with the spreadsheet.
P.S: this example is for EEVX2.1 or greater and Excel 2010
Hope this helps