You can't terminate this work relationship because it's set to be primary in future

Hello,

I have a user in the system who should definitely be terminated with the termination date of May 31, 2024.
The user has multiple assignments (two Inactive and terminated, and one Active).

I'm unable to terminate the work relationship because it is blocked by the system and generates the "primary work relationship flag" warning.

This is the "Active" assignment status:

I'm not able to change the primary work relationship as of 31.05.2024.

How can I resolve this issue?

Thank,
Antonio