Hi, it's not possible to automatically convert your ISA holdings. So unfortunately you would simply have to sell them and then repurchase those you want to continue holding in a non-ISA account.
When you've paid into more than one shares ISA in the same year, however, HMRC advise that you don't try and fix this yourself. Instead you should first call their helpline for advice - 0300 200 3300. It shouldn't be a major problem as long as you haven't made capital gains beyond the £12,300 annual allowance or received significant dividends. But failure to disclose the error could result in pena