What is the proper salutation in a letter to someone with PA after their name?

In a letter to someone with "PA" (which stands for "Professional Association") after their name, you would typically use a formal salutation. A suitable salutation would be "Dear [Full Name],". If the letter is more formal, you might consider using "Dear Mr./Ms. [Last Name],". Always ensure to maintain a respectful tone appropriate for the context of the correspondence.