How to use uppercase in approval spreadsheet

Summary:

Hi,

I am writing approval rules based on user name e.g. if a user is abc@xyz.com then it should route to pqr@xyz.com. I am using spreadsheet to upload rules. How should I make it not dependent on case of user case so that it works fine even if user is aBc@xYz.com or if it is abc@xyz.com ?

Regards,

Gaurav

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