How to create a new rating model for potential assessment

Summary:

I have created a rating model with 10 level starting from 1 to 10 for Potential assessment now i want to change it to 5 levels only . How can i do that ? The rating levels can not be deleted and if i create a new rating model for potential assessment it doesnt get linked to the potential assessment questionnaire

Content (required):

Looking to have information on how to update the potential assessment rating model

Version (include the version you are using, if applicable):23 C

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