Current graph query languages, including the standards SQL/PGQ and GQL, define their semantics in terms of sets of tuples. This is largely inadequate for data interoperability tasks such as data migration or data integration which require queries to output new property graphs. This demonstration showcases DTGraph, an opensource declarative rule-based framework for easily specifying and efficiently executing property graph transformations. We describe a novel comprehensive system that allows the declarative specification of property graph transformations, by extending openCypher queries with a new GENERATE clause for creating new property graphs. The system includes several modules: a parser, a compiler for translating the transformation logic into an efficient executable openCypher script, and an interface assisting users in developing their transformations. The demonstration showcases the ability of our framework to scale to large graph data, and its suitability for transforming real-world datasets.