This is the @handle associated with a contact's account.For an internal contact it appears as @{handle}. Make sure you send the request without the @ character. For example, if the Contact's @handle is @borderless simply submit borderless in the handle field.

A Client Internal Reference or CIR is way for your company to internally label a contact. This can be used for grouping various contacts in a category, like EngineeringTeam. It should be between 1 and 60 alphanumeric characters and accepts only spaces as special characters.