Microsoft recently added a support article that describes the steps to migrate a 3.x SoftGrid database from one SQL Server to another.   It is recommended to perform these steps during a scheduled downtime:
 

Prerequisites

The SQL Server that the SoftGird Server is currently configured for, will be referred to as the "source SQL Server" while the SQL Server that the database will be migrated to will be referred to as the "target SQL Server".

It is recommended to perform these steps during a scheduled downtime.

It is also recommended to stop the SoftGrid Virtual Application Server service prior to starting the migration. If the SoftGrid Virtual Application Server service is not available to the SoftGrid Clients, the SoftGrid Clients will go into Minimal Disconnected Operation (MDO) and continue to stream applications that are loaded 100% in cache. If however, the SoftGrid Virtual Application Server service is available but the migration is incomplete the SoftGrid Clients may not be able to enter MDO and will receive a launch failure.

Read the entire support article, here.