if cell includes string, append a character to the value of another cell.

Before looking ad your examples:

1) I can't help you enough with VBA.

Sometimes they used ";" and other times they used ",". There are also random carriage returns and extra trailing spaces in different cells

2) Work with datavalidation

3) For the future, you can use the same workbook for the before an after situation.
You can use differnt worksheets.

i attach a workbook with the before an after situation.

Maybe you can point us, where we can find the cells that need to be changed.