This inquiry explores the features of request sequences in Chinese public service calls. The data assay denotes that an important feature of Chinese public service calls is the recurrent emergence of insert extensions and non-minimal post-extensions, with the latter transpiring after both preferred and dispreferred response. This is tightly linked to participants’ institutional identities and epistemic asymmetry; operators addressing such service calls should pay proper attention to this asymmetry to protect reciprocal comprehension in conversation.