> 
> **Possible Duplicate:**  
> 
> [PHP date time](https://stackoverflow.com/questions/842974/php-date-time) 
> 
> 
> 

Trying to add one second to a datetime that is input by the user
$values['start\_date\_'.$j.'-'.$i] is a valid datetime string, however the following code is throwing an error 

```
$priceStart = date('Y-m-d H:i:s',strtotime($values['start_date_'.$j.'-'.$i]));
date_modify($priceStart, '+1 second');
$priceStart =date_format($priceStart, 'Y-m-d H:i:s');

```

The error is "date\_modify() expects parameter 1 to be DateTime, string given in... on line..."
same error follows for date\_format()

what is the correct syntax for this?