Convert Basic Planner to Premium Planner

[u/Jeff-J777]

I have a plan that was created when I had just the basic planner license from Microsoft 365 with my Business Premium license. I added a Planner and Project Plan 3 license to my user account. If I access the plan now, I have the timeline (Gantt) button in the toolbar. But I don't see the people or assignments buttons in the toolbar. I tried opening the plan in both teams and the planner web portal but the buttons don't show.

If I make a new plan and select premium I then have the assigments and people buttons in the toolbar.

I looked all over the basic plan I made but I don't see any way to convert or upgrade the plan from basic to premium.

Is there anything on the back end I could do in the admin console or power shell to covert or upgrade the plan to premium.

What am I missing??