Can existing Delta tables be converted into DLT?
Delta Live Tables is actually the pipeline that manages the table, so you don't need to “convert” a delta table, you just migrate the pipeline to a Live Tables pipeline.
Migrating an existing pipeline to Delta Live Tables is mostly refactoring the code which writes to a delta table. It still uses your existing transformations and data sources.
Instruction: Can existing Delta tables be converted into DLT?
Context: 
Response: Delta Live Tables is actually the pipeline that manages the table, so you don't need to “convert” a delta table, you just migrate the pipeline to a Live Tables pipeline.
Migrating an existing pipeline to Delta Live Tables is mostly refactoring the code which writes to a delta table. It still uses your existing transformations and data sources.