how to construct a negative heterogeneous graph example?

Hello everyone, I am trying to using rgcn form dgl to get an embedding of each node of a heterogeneous graph with features, and I want to construct a negative heterogeneous graph to compute the loss by using positive graph embedding subtract negative graph embedding. I am wondering how to construct a negative graph. Considering each edge in heterogeneous graph as a triple (src, relation, dst), here are three solutions I have thought.
1. In each relation, find a src and change the dst.
2. find an src and an dst, change the relation
3. both 1 and 2,