To move Profit and Loss accounts, go to Reports (top bar) > P&L (any P&L Report from the left sidebar)> Edit (top right) > Edit Report > Configure base Profit & LossĀ (near top middle).
To move Balance Sheet accounts, go to Reports (top bar) > Balance Sheet (any Balance Sheet Report from the left sidebar)> Edit (top right) > Edit Report > Configure base Balance Sheet (near top middle).
Click Expand all to see all accounts in any Financial Category. > Tick the box to the left of the account or accounts you wish to move > Click Move to (top of page)>Select the Financial Category, Group, and Sub Group to which you want to move the account and click on it.