You can make schema changes in your production database without locking it, using online schema change tools like PlanetScale. Instead of applying changes directly to a table, you create a copy of the table (shadow table), apply the schema changes, get the data in sync between both tables, swap the tables atomically, and drop the old table. This process is non-blocking, meaning it won't lock your database during the schema change. PlanetScale handles this workflow for you with their branching feature, allowing you to make schema changes without downtime or data loss. The key is to run migrations on a development branch before deploying changes to production, ensuring that your application code doesn't write to the new schema until it's live in production. This approach simplifies the process of making schema changes and reduces stress for developers.