Hello @Akki1 ,

Refer below article as a example and update field names and other things as per your req:

function onChange(control, oldValue, newValue, isLoading) {
    if (isLoading || newValue === '') {
        return;
    }

    // Get the value of the dropdown
    var dropdownValue = g_form.getValue('your_dropdown_field');

    // Update the client state parameter based on the dropdown value
    g_scratchpad.clientStateParameter = dropdownValue;

    // Optionally, you can use the value to filter a list
    filterListBasedOnDropdown(dropdownValue);
}

function filterListBasedOnDropdown(value) {
    // Implement your logic to filter the list based on the dropdown value
    // For example:
    var gr = new GlideRecord('your_table');
    gr.addQuery('your_field', value);
    gr.query(function (gr) {
        // Process the filtered list
    });
}