How to replace a user control by another one in the same page ?

Hi all :)
 
suppose that I have a placeholder with ID=ph1 htat hold a user control and has a button
and I ahve two user controls with IDs, uc1, uc2
and using my button I want to replace my uc1 by uc2 in the same page
 
is that possible ?
 
I use C#.Net in my project
 

...