A recognition that their own knowledge is limited and that they could be wrong.
You can actively train your mind to be more expansive by following these practices suggested by Indeed and Vision Times : Broad-minded - Definition, Meaning & Synonyms broad-mindedness
The ability to understand and share the feelings of others, even when they disagree. A recognition that their own knowledge is limited
The ability to adjust perspectives when presented with new, valid evidence. Steps to Develop Broad-Mindedness valid evidence. Steps to Develop Broad-Mindedness