Hi,
If you mean can you edit the source list of say a Data Validation List, the
answer is yes. If you mean can you edit the list that is displayed in the
drop down, the answer is you can allow entries that are not on the list by
setting the Style to Information on the Error Alert tab of the Data
Validation dialog box. If you mean can you edit in the cell and have that
change added to the Source list automatically, for that you will need to
write VBA code.