What is the term for a formal warning issued to an employee?

The term for a formal warning issued to an employee is "to serve notice." This phrase is commonly used in employment contexts to indicate that an employee has been formally informed of a performance issue, policy violation, or behavioral concern that requires their attention. Serving notice typically entails documenting the warning and communicating it clearly to the employee, outlining expected improvements or consequences if the behavior does not change.

The other choices do not accurately represent the formal nature of a warning. Providing feedback might refer to informal comments about performance but lacks the official status associated with a formal warning. Initiating a discussion suggests a more conversational approach, while escalating an issue generally indicates moving a concern up the chain of command, which is not synonymous with issuing a formal warning.