How to push id to relation array

Hello guys.

How can i push newId to relation array like this […oldValues, newValues] via API request?

PUT ereases old values

POST i think is impossible

Any other solution or maybe changes in backand needed?

System Information
  • Strapi Version: 4
  • Operating System:
  • Database:
  • Node Version:
  • NPM Version:
  • Yarn Version: