While a transaction has not been invoiced, it is possible to switch the account or address on the transaction.
While viewing the transaction:
Click Edit.
Click on the Addresses tab.
Click Switch Address and select the new site address.
Click Save.
If the new site address is on a different account, the account and account address will also update on the transaction. If the address does not already exist under the account the transaction should be linked to, you will need to create it first.
If the pre-invoicing report shows the transactions linked to multiple accounts, this indicates a change has been made which is referencing two accounts (e.g. all links not updated when using full edit, only address changed via move records). The above steps will also correctly link the transaction to the target account.