Is there a way to hide buttons in a form to show a preview only ?

My B plan is to create another form where I'll not keep the data. But I'm sure there is something else. 

Another option could be to cancel submit if Preview==true (or something like that...), but I don't like the message : 

Invalid entries found. Please correct and submit again

and

Failed to add data

Can I change these messages ?

Thanks,

Pascal | nsisolution