Epigenetic modifications play key roles in regulating transcription by altering chromatin structure and accessibility in response to internal cues or external stimuli. Here, we present a protocol for assessing bivalent histone modification changes through chromatin immunoprecipitation (ChIP)-reChIP assay in response to warm ambient temperature in Arabidopsis. We describe steps to perform transient warm ambient temperature treatment on Arabidopsis seedlings. We then detailed procedures for ChIP-reChIP, which can be applied to investigate various DNA-protein interaction dynamics in different experimental contexts. For complete details on the use and execution of this protocol, please refer to Shao et al.(1).