what do u do if

Don't worry about it. It's not unusual to find two in one nesting box. Once I found three stuffed in the same box (And there were several boxes empty)!
I'm assuming you mean for laying purposes and they're not setting on hatching eggs.

 

Don't worry about it I: sometimes have three, I ask them just what are they doing , all I get is clucks and eggs, so happy blending.

 

As long as they are not hurting anything let them be.

 

My girls did this for a little while when they first started laying. My dad said they were lesbians.