A long time ago in a galaxy far away (before the internet was a normal thing to have) I provided over-the-phone support for a large and complex piece of software.
So, people would call up and you had to describe how they could do the thing they needed to do, and if that failed they would have to wait a few days until you went to the site to sort it in person.
The software we supported was not on the approved list for the company I worked for, so you couldn’t use it within the building where the phones were being answered.