Can the My Chart of Accounts Utility Merge Accounts?
Unfortunately the utility can not be used to merge two accounts into one on a QB Chart of Accounts list.
It can be used to add and remove sub or parent accounts. It's possible to restructure the hierarchy of accounts, but it will not merge two accounts into a single account name. That activity can only be done through the QuickBooks interface AFAWK (as far as we know).
QB Utility Support