You are allowed to switch between offered Trading Platforms for accounts where no trade is placed. If a deal is placed, you can request to switch after you reach the next phase, or if it is a Pro Account you can request to switch after full payout is requested and the account is back at Initial Balance.
Learn the Platform Switch Criteria for other programs. (Hyperlink to Account Rule section on the question: ‘Can I Switch My Account Between Offered Trading Platforms?’