Planning lock on order &1 in assigned investment program

What causes this issue?

You want to change plan values for order &V1&. An investment program
position is directly or indirectly assigned to this order. A planning
lock is in effect for program type &V2&, approval year &V3& and
authorization level &V4& in the requested plan version.

System Response

Planning for order &V1& is not possible.

How to fix this error?

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

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.