Available in Sage 50 Accountant Edition.

Adding, Modifying, or Removing Accounts

You can rename a linked account and it will not affect the link.

You can only remove an account if:

You have finished entering your company's historical information.
The account has a zero balance.
It is not being used as a linked account in your company.
It has not been used since the earliest transaction date.
The account has not been used in transactions belonging to the current or previous year.
The account has not been used in transactions belonging to the next year. (Sage 50 Premium Accounting)