This can be resolved by updating the SQLServer field in the FSAReportingDatabase table within the EnterpriseVaultDirectory database to point to new SQL server.
 

Note: It is recommended that these steps should be performed with guidance and that the EV database should be backed up before updating or deleting any records.

1. Login to SQL Server with Admin credentials.
2. Open SQL Management Studio.
3. Click on New Query and execute following query:

USE EnterpriseVaultDirectory
UPDATE FSAReportingDatabase
SET SQLServer = ''

For example,
USE EnterpriseVaultDirectory 
UPDATE FSAReportingDatabase 
SET SQLServer = 'SQLServer2'