Try using the $new_line string constant in the report designer function editor.
Example which replaces all occurrences of 2 spaces with a new line, Formulas: vldtstr:strReplaceAll('Line 1 Line 2', ' ', $new_line) Output: Line 1 Line 2
If you are unable to achieve this in report designer, I would suggest you to do the changes on the RDF logic.
Try using the $new_line string constant in the report designer function editor.
Example which replaces all occurrences of 2 spaces with a new line, Formulas: vldtstr:strReplaceAll('Line 1 Line 2', ' ', $new_line) Output: Line 1 Line 2
If you are unable to achieve this in report designer, I would suggest you to do the changes on the RDF logic.