You should be able to transfer money between your Pots between any account, personal or joint! So for example, you can transfer money from your Personal savings Pot to your Joint savings Pot, and vice versa. You won’t be able to move the actual Pot to the other account so you’ll need to create a new Pot in your joint account.
We’re working on scheduled and recurring account-to-account transfers so this should be available soon. 
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Side note: I suspect pot-to-pot transfers are only available in the US right now 