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1. Create a Custom Report type for Chat Transcripts object.
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2. Create a report using the report type created from the step1.
3. Create a formula field in the Report to find the hour of Chat Transcript End Time.
Formula:
LEFT( RIGHT( TEXT( LiveChatTranscript.EndTime – ( 4/24 ) ), 9 ), 2 )
Note:
I haveused GMT-4 for the hour calculation. You can adjust it as required.
Reference Link:
https://help.salesforce.com/s/articleView?id=000319411&type=1
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Output:
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Video Reference: