xml error

I need help to fix the error in xml file..

normally every xml get <gen:DocumentAttestationDate>2016-03-01</gen:DocumentAttestationDate> tag properly formed...

but in some of the xml it is coming like this :-
<gen:DocumentAttestationDate>

2015-09-07</gen:DocumentAttestationDate>

which means there is space after the opening tag which is pushing the date in next line.. how to get data in same and closing tag in same line as starting tag...

thanks for your help