If a property has transferred from one landlord/agent to another, you should not transfer the tenant property. This is because, when a transfer is carried out, all history including invoices and debt are then attributed to the new landlord/agent.
These feature should therefore only been used if a tenant has been created under the incorrect agent/landlord.
If you have created the tenant under the wrong agent, go to the tenant details and click on Actions > Admin Tools > Transfer
Search for and select the new landlord.