You need to update all existing records in your database that include this enum value and that have value 3 (and also 8, if you already have some pre-existing option that uses number 8).
Also if you have any code that relies on the numerical value (including "less than" / "greater than" operators) instead of EnumName::Option, it will need to be adjusted.
Why do you want to change it? Is it a standard enum or something you developed?