The reason that you can't do this Online self-service is because "Individual" lines are not meant to have "other plans" added. This was a design limitation, they never envisioned a "wearable" when they were setup. However the $10 AT&T Unlimited Wearable Plan is a "Special" plan and not a normal cellular device in Carrier speak.
So you have to call or stop by a Corporate Retail location. The reason that I don't mention Dealers or Authorized Agents is because there is no money in for this type of service. They get commission for everything they do for AT&T. A Corporate Retail also earns commissions but they have to do everything even if there is no real commission value in a $10 AT&T Unlimited Wearable plan.
If you were a cynic you might think, hey that's way the reps always want to "add new lines of service", and upgrade your old low value plans. While this does motivate some reps so they can hit their commission plan challenges, many reps just don't know about all the plans, devices and one off add-ons.
Dave
So you have to call or stop by a Corporate Retail location. The reason that I don't mention Dealers or Authorized Agents is because there is no money in for this type of service. They get commission for everything they do for AT&T. A Corporate Retail also earns commissions but they have to do everything even if there is no real commission value in a $10 AT&T Unlimited Wearable plan.
If you were a cynic you might think, hey that's way the reps always want to "add new lines of service", and upgrade your old low value plans. While this does motivate some reps so they can hit their commission plan challenges, many reps just don't know about all the plans, devices and one off add-ons.
Dave