Here are the steps to merge accounts:

1.    From Main Menu > Lists > Chart of Accounts to open Chart of Accounts window.  Then, highlight the account that you want to merge and press Ctrl + E to edit it.  Below is the example of merging Shipping Charges  expense account to Freight/Shipping expense account.

2.    In the Edit Account window of the account you want to merge/eliminate (Shipping Charges), go to the Account Name field and change it to the account you want to keep (Freight/Shipping).  You have to type exact letters &/or numbers of the account.

 

QB Merging Accounts 1

 

3.    Click Save & Close.  QuickBooks will prompt you with the following message:

 

QB Merging Accounts 2

 

4.    Click Yes and it’s done.  All your Shipping Charges account transactions will be brought into Freight/Shipping account and you now only have Freight/Shipping account.
The Shipping Charges expense account is removed from chart of accounts.