Add Relationship type to Case Contact

Summary:

Relationship field has been enabled in the CaseContacts layout. However, we are not getting option to choose the relationship type. It is not editable field.

Content (required):

Relationship field has been enabled in the CaseContacts layout. However, we are not getting option to choose the relationship type. It is not editable field. Could anyone please share your inputs on how to make it editable to select the value?

Version (include the version you are using, if applicable):

23B

Code Snippet (add any code snippets that support your topic, if applicable):

This screen-shot is from Case page

Application Composer