I believe an expense receipt I have received for an Uber ride from an employee is fake. Am I legally allowed to contact Uber and ask them to verify the receipt? If I suggest to the employee i think the receipt is fake that is a serious accusation. I would rather validate the receipt independently with Uber first. Is that possible/allowed because it's not my Uber account?
You cannot validate it because the employee used his personal Uber account and Uber would breach customer's privacy if they told you about a transaction you are not a party to.
Consider using Uber for Business or give your employee a business credit card so that you could track the expenses.