The following should work for your use case.
If REGEX_Match([Column1], '([A-Za-z])(\s)(.+)') then Regex_Replace([Column1], '([A-Za-z])(\s)(.+)','$1') else null() endif
If REGEX_Match([Column1], '([A-Za-z])(\s)(.+)') then Regex_Replace([Column1], '([A-Za-z])(\s)(.+)','$3') else [Column1] endif
Use a RegEx tool and use the following expression: (.)\s.*
Set the output method to parse and set column to parse as your column 1. Attached is a sample workflow for reference.
Below is a screenshot of the same.
This regular expression finds your single character followed by a space if it exists, if it cannot find that pattern, it returns null.