Search through columns and find specific text and replace that text with header column

I need help with a macro that searches through columns of a table and picks up the letter x and replaces the letter x with the header of that particular column.
Once the letter x has been replaced with the header, the structure of the data changes from a table to list the items that have changed from x to the headers downwards.

I have attached an example file.

Any help would be appreciated.