You can restrict Delete Permission by setting the Profiles under Setup > Admin Settings > Profiles. You can either edit the default Standard Profile or add a new Profile and un-check Delete options for the modules and save the Profile. Now, associate ...
You can restrict this at Profiles. Goto Setup >Admin Settings >Profiles Edit the standard profile or create a new profile and un-check the option Customize Zoho Support under Admin Options. Associate this Profile to the Support Agent (Setup >Admin ...