How to show impartiality in the QMS?

In this case you will be focussing on internal issues, personal relationships, or other conflicts of interest between operations and quality activities. Ion these situations, impartiality can be safeguarded by establishing clear measurable quality objectives and a commitment as operations manager that decisions will not be taken which could impact the quality objectives. Use independent internal auditors to ensure fair unbiased decisions are evident. For example not taking on more work that the laboratory can cope with, nor putting unfair pressure on laboratory personnel to rush results by taking shortcuts. Any identified risks must be addressed and resolved.

For more information, have a look at the advice answers

Compliance with the ISO/IEC 17025:2017 requirement for Impartiality - https://community.advisera.com/topic/compliance-with-the-isoiec-170252017-requirement-for-impartiality/ 
Procedure for impartiality - https://community.advisera.com/topic/procedure-for-impartiality/
The ISO 17025 document template: Registry of Key Risks and Opportunities, is available for purchase -https://advisera.com/17025academy/documentation/registry-of-key-risks-and-opportunities/