How do I add the area externally in the hard disk utility on the MacBook Pro after it has been deleted?

Accidentally deleted the external area in Disk Utility a few days ago when my Macbook couldn't read an old hard drive that was previously needed for a Windows laptop.

How do I add the range back in Disk Utility? I no longer see any external hard drives, either there or under Places in the Finder.

Hope someone here knows a solution.

The external area is only available again when an external HD is really connected.