Query Related Edit Version able Item

Hi All,

I have question related to Edit version able Item.

Let suppose . I want to edit Item Type user Guide. User Guide Number is Doc*25

and Generation 10.

I logged with user  X and edit User Guide Number  Doc*25 next and Generation 11 has been created.

Note : I do not want to close User guide Item Type with Generation 11.

After some time User Y logged in  innovator Modified user guide of Generation 11.

After edit user guide by User Y  Generation become 12.

And after That User X already keep Open Generation  11 of User guide.

User X modified Generation  11 of User guide. 

And then what  happened All change done  Generation 12 by user Y has been losses after modified by user X of Generation 11.

How to handle this situation by Configuration ?

Regards

Ashok Kumar Yadav