Overturning a call

Question
During our U12 ASA girls slowpitch game, the home plate umpire(the only umpire on the field) made an "out" call at 1st base.  Upon complaints by the opposing coach, the umpire asked my first baseman if she tagged the runner and being an honest 11 yr. old, the first baseman said that she missed her - the ump then changed his call to "safe".  First of all, can he change his call based on the complaint of a coach?  Secondly, is the umpire permitted to ask my player whether or not she tagged the runner?  

Answer
Hi Brad,

I really don't know how to answer this because it sounds like this umpire is not very experienced and we don't have rules that specifically address your questions.

A 1 umpire game is tough because you can't see everything. I guess I would have to say an umpire in 1 man league play can do whatever they want to within reason.  I didn't say letting the player make the call is a good way to handle the situation.

Mark