you can use this method just pass your date to it
-(NSString *)getDateFromString:(NSString *)string
{
NSString * dateString = [NSString stringWithFormat: @"%@",string];
NSDateFormatter* dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"your current date format"];
NSDate* myDate = [dateFormatter dateFromString:dateString];
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"your desired format"];
NSString *stringFromDate = [formatter stringFromDate:myDate];
NSLog(@"%@", stringFromDate);
return stringFromDate;
}