PIPs are generally used in instances where improvements in performance and behaviour are required. Our process is to have an informal chat, a file note, PIP (a record which explains the reasoning and what actions you have taken together to reach the improved standards, and what further action may be taken if these standards are not met) then further disciplinary action.
Please often view PIPs as a negative thing however it depends on how it is delivered. Where support is required, you need to deliver a positive message so the agent understands you are supportive of their improvements and willing to work together to attain them.