EHP6 update on Windows cluster failover issue

Hi,

We are doing EHP6 update from ERP6 EHP5 on Windows cluster 2008 R2, SQL server 2008.

As per SAP recomendations the cluster nodeA needs to be disabled after moving all the cluster resources to NodeB before actual downtime starts.

what is the possibility to proceed in downtime if the cluster resource DB is on NodeA and ASCS, MSDTC on NodeB, and we are not able to move the resources.

If we have no other option except this situation, then when and what should be taken care?

Thanks in Advance.

Regards

Munish Jindal