Stop all writes to the source MySQL server
Allow 30 seconds for all the writes to get propagated.
Ensure the replica lag of ScaleGrid Servers is zero
When the replica lag is zero, it indicates that source and destination are in sync
Change your connection string to point to the ScaleGrid deployment. (but don't start your application yet.)
Click Complete live sync to complete the live sync.
Once you click complete live sync, no further writes to the source MySQL will be replicated.