Updating excel sheet

HOW DO I UPDATE A COLUMN VALUE IN THE LAST ROW OF AN EXCEL SHEET?

@Neya
1.Read the excel sheet and store it in a datatable dt
2.use add datarow Activity
3.In Add DataRow, mention datatable variable, and initialise datarow by using dt.new Row
4. Then in Assign Activity give dt.Rows(dt.Rows.Count-1)("Column Name)= Value

Regards,
Mahesh