For existing segments or complex segments that you wish to split into a new segment(s), there is currently no functionality on the Platform to split the existing segment. Creating a new segment is the only way to capture any guests from an existing segment. For example, you can use the option to Freeze a segment or to export the current segment and make a Custom List segment.
If further assistance is required, submit a ticket to Punchh Support. (For help submitting a ticket, click here)