I am trying to replace a comma from a single line of text field with an underscore(this I managed to do), but I want to replace it if a certain criteria is met - if the value in the field contains a comma to replace it with an underscore and if it doesn't, to leave the field with the value it already has. Here's the formula I managed to put together and only the part where it replaces the comma with an underscore works. If the field doesn't contain any commas though it just puts #VALUE!
inside of the calculated field.
=IF((FIND(",",[TestField])),REPLACE([TestField],FIND(",",[TestField]),1,"_"),[TestField])