Find pattern and replace with everything after pattern vim

I have a file which has contents like so:

size is X1 Identifier is Y1
size is X1 Identifier is Y1
size is X1 Identifier is Y1

I want to re-arrage the file so that I get

Identifier is Y1 size is X1 
Identifier is Y1 size is X1 
Identifier is Y1 size is X1 

How do I do this using vim find & replace? Or any other function in vim?