Changes relevant to approval not allowed, since contract in workflow

What causes this issue?

Changes requiring approval are not allowed at the moment, since the
contract is still in workflow <ZH>&V1&</>.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.