Thank you for reaching out.
You can run the Front Doors - Create Or Update Rest API to disable your Azure front door cdn profile ( Azure Front Door Classic tier). I tried it on my end and was successful in disabling the profile.
In order to set the request body in required format for the Rest API above, I will recommend that you run the Get API all first and then use the response you get as request body in the update rest Api.
You have to set the field marked below as Disabled in your request body. This field will be at the end of the JSON body. I had to wait for few minutes (5-10 mins) before the profile was disabled.
Hope this helps!
Please "Accept the answer" if the information helped you. This will help us and others in the community as well.