This document allows the employer confirm a Verbal Warning, and to specify the exact misconduct and the improvement timescale to the employee.
Verbal warning confirmation (general) template
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Good email etiquette
Email etiquette refers to the principles of behavior that one should use when writing or answering email messages.
Declaration of consent to reference
If you are requesting a reference for a new joiner from a previous employer, the new joiner must give you authorisation to approach their former employer to share their personal details to you.