I just realized that I'm unable to change Location Modes from either a classic routine or Webcore

“Location.mode” is a term used in the new app (“smartthings (Samsung connect)”) To distinguish what used to just be called “modes” in the classic app from “security.modes” ( which are called “smart home monitor armed states” in the classic app).

If you’re confused about the difference between these two kinds of values, see the following FAQ:

Anyway…

“Routine” is a term used in the classic app for a specific type of automation.

So I’m pretty confused by your post because you are using a term from the new app (location.mode) With a term from the classic app (routine) and those two can’t go together.

You can use a routine in the classic app to change a mode in the classic app.

If you happen to be running both the classic app and the new app, which some people are doing, you could actually have three different kinds of modes:

Location.mode ( accessible from automations created in either app, including classic routines and webcore, but called just Mode in the Classic app)

Security.mode (accessible only from automations created in the new app)

Smart Home Monitor Armed State ( accessible only from automations created in the classic app, including routines, webcore, and the Classic app’s smart home monitor)

Location” Is a fourth value, something altogether different, and is essentially a sub account to your smartthings account. In the classic app, you could sign out and sign back in to a different location. In the new app, you can switch from one location to another in the app without having to sign out. As far as I know, you can’t change from one location to another except by manually going through that app with either app.

(There is also a “secure mode” associated with zigbee devices, but most people won’t run into that one and you don’t set it with an automation.)

So, like I said, I’m confused as to exactly what it is that you were trying to do and therefore just what it is that you are unable to do. Could you give a more specific example? What’s the value of what you were trying to change with Webcore and how did it get set in the first place.

References:

Classic app

https://support.smartthings.com/hc/en-us/articles/200962880-How-do-Modes-work-in-SmartThings-Classic-

New app

https://support.smartthings.com/hc/en-us/articles/115002056383-Custom-Automations-in-the-SmartThings-app