The easiest way that I can think of on the top of my head is to use the other built-in system variables for day, month and year this way you can format the date any way you want without changing the date system variable.
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Alternatively, Automation Anywhere bot store has a free metabot package called "Change Date and Time Format" that you can download. This has a DLL built into it called changeDateFormat that takes a "culture" as a variable, you can check the documentation i bet it has the format you’re looking for.