How to add hours to a parse moment date?

I just want to ask if it is possible to add hours to a parse moment date. I have a code like this:

var myDate = "2017-04-14 07:07:15"; 
var object_myDate = moment(myDate).format('YYYY-MM-DD hh:mm:ss');
var status = object_myDate.add(5, 'hours');

but this code gives the following error:

object_myDate.add is not a function

add is a moment function, you should use on moment object:

var myDate = "2017-04-14 07:07:15"; 
var status = moment(myDate).add(5, 'hours').format('YYYY-MM-DD hh:mm:ss');