Disable the "Delete" option for Edit Phone Details page

Summary:

We have a requirement to disable the "Delete" option under Person Management -> Person -> Edit Phone but when trying to do it using Page Composer it is not working.

Content (required):

We have a requirement to disable the "Delete" option under Person Management -> Person -> Edit Phone but when trying to do it using Page Composer it is not working. I am facing the following issues:

1. When opening the Edit Phone Details page, a new small window opens up and the back page where we select the structure option for page composer is greyed out. Hence unable to access the page composer.