In WebTools Express you can select an automatic roll switch setting:
[Roll empty: when a specific roll number is set]
You can choose one of the following actions:
[Switch to a similar roll (same type, same size)]
The printer automatically continues printing on an identical (size and media type) roll when the selected roll runs out of media. If no identical roll is available, the job is stopped and the printer requests to load new media.
[Always ask to replace the empty roll]
The job is stopped and the printer requests to load new media.
This setting has no influence on jobs for which only a media size was selected. For these jobs, the Media Selection Policy determines if a new roll can be selected.