public class TimeZoneServiceNew{
    
    public static string EST='America/New_York';
    ///Convert Any time to other timezone
    public DateTime convertDateTimeToOtherTimeZone(DateTime dttime, string sourceTimezone, string targetTimezone)
    {
        TimeZone tz = Timezone.getTimeZone(sourceTimezone);
        System.debug('Display name: ' + tz.getDisplayName());
        System.debug('ID: ' + tz.getID());
        
        Integer offset=tz.getOffset(dttime);
        System.debug('Offset: ' + offset);
        
        // target Timezone.
        TimeZone targetTZ = Timezone.getTimeZone(targetTimezone);
        System.debug('Display name: ' + targetTZ.getDisplayName());
        integer offsetTotargetTZ = targetTZ.getOffset(dttime);
       	integer correction = offsetTotargetTZ- offset;
		    
        DateTime targetDT = dttime.addMinutes(correction / (1000 * 60));
        
        //return Time.newInstance(targetDT.hour(), targetDT.minute(), targetDT.second(), targetDT.millisecond());
		return targetDT;
    }
}