Why can't I reassign my premium subscription to another wix site I just built?

why can’t I reassign my premium subscription to another wix site I just built?
when I try to reassign it only one of my website show up, though I have 6 website in my dashboard that are unassigned

Wix Studio

What are you trying to achieve:
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What have you already tried:
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Additional information:
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You must be the owner of both sites to assign a premium plan.

If you still can’t assign it, you may need to open a ticket with Wix Support.