The string 'MMMM/dd/yyyy' was not recognized as a valid DateTime. There is an unknown word starting at index '0'

Hi @kmilo_de_los_santos

Welcome to Community!

Try with this expression

DateTime.ParseExact("ENE/15/2022",{"MMM/dd/yyyy","MMMM/dd/yyyy"},System.Globalization.CultureInfo.GetCultureInfo("es-ES"),System.Globalization.DateTimeStyles.None).ToString("MMM/dd/yyyy")

Regards
Sudharsan