i need to change the format of a cell when someone replaces the formula
(SUMIF formula)of a cell and enter the number manually, and apply this format
to a column of cells.

For example the prices in the cells are calculated using the (SUMIF) formula
to fetch the price from the price list sheet compared with the part number,
sometimes we need to modify the price for a certain part number (special
price, €¦etc.) so we will enter this price manually, and we need to change the
format of this cell to show these price modifications.