Error and Conflict Handler (CA-FS-ECH) 
You use Error and Conflict Handler (ECH) to control the response to business errors and conflicts as part of asynchronous processing.
To use Error and Conflict Handler, in Customizing for Cross-Application Components, choose .
Error and Conflict Handler uses the internal components Postprocessing Office (PPO) and Hierarchical Derivation Service (HDS):

PPO creates and processes postprocessing orders. HDS determines the suitable resolution strategy for error correction, specifying postprocessing activities that are available.
Error and Conflict Handler includes the following functions:
You make the settings for the functions in Error and Conflict Handler in Customizing for Cross-Application Components under .