Here's a simple breakdown of the process regarding deleting custom option within the Advanced Product Customizer admin panel and your Shopify store:

1. Step 1:

   Go to the options list tab

   

2. Step 2:

   From the options list, click on the delete button for the single line text option which needs to be updated.

   

3. Step 3:

   Click on Yes button for deleting single line text option.