If value used elsewhere then conditional formatting
On one of my sheets we have a column with order reference numbers with the following format XYZ0123. I have been trying to set up a conditional format to warn me if I am reusing a previous number further down in the same column. So, if I enter ABC0345 and it has already been used in one of the cells further down the same column, the new cell will turn red. The conditional formatting part is simple but I cannot identify a syntax for "if value entered = value in any other cell in this column apply format". I can do this in excel but if this function available in Smartsheet? If not is there any other way to achieve the same thing?