the common law favors the freedom of assignment, so an assignment will generally be permitted unless there is an express prohibition against assignment in the contract. where assignment is thus permitted, the assignor need not consult the other party to the contract. an assignment cannot have any effect on the duties of the other party to the contract, nor can it reduce the possibility of the other party receiving full performance of the same quality. certain kinds of performance, therefore, "cannot" be assigned, because they create a unique relationship between the parties to the contract. for example, the assignment of a legal malpractice claim is void since an assignee would be a stranger to the attorney-client relationship, who was owed no duty by the attorney and would imperil the sanctity of the highly confidential and fiduciary relationship existing between attorney and client.