Make sure to have a working backup or copy of your data file.
Highlight the transactions that you want to move.
To select multiple contiguous transactions, click the first transaction and hold down SHIFT - click the last transaction
Use CTRL for non-contiguous transactions.
Right-click (CTRL-click for Mac) any one of the highlighted transaction in the register.
From the resulting context menu, select Batch Change > Account
Select the account that you wish to move the transaction into.