First ,i would say it is not supported operation from cisco. Changing the collation could bring the system to corrupted state. I see a note in the staging guide
"it is critical to select the correct collation setting for the end user's language display during installation. If you do not select the correct collation during installation, you must uninstall and reinstall Microsoft SQL Server."
http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cust_contact/contact_center/icm_enterprise/icm_enterprise_10_5_1/Installation/Guide/UCCE_BK_S737967D_00_staging-guide-for-cisco-unified/microsoft_sql_server_2008_r2_staging.html