Diagnosis
You want to reassign object &V1& in the hierarchy (for instance, bychanging the superior building).
This would position it below object &V2&. As object &V2& istenant-rented with contract &V4&, it would likewise be tenant-rented inthis period. However object &V1& is tenant-rented itself with contractV3. as the periods overlap, this would mean that the object is tenantrented twice.

System Response
Multiple tenant rental is not permitted.

Procedure
Remove object &V1& from its tenant rental agreement before changing theobject hiearchy.