Hi

I dont see any benefit in calling a UI page in a business rule, because all BRs works server side and UI page operates at client.

So I would suggest you to call a UI page from cleint script.

Steps to Casl a UI Page from client script

1. Create a UI page "abc" and put your content in the same

2. Call it via below script:

var gdw = new GlideDialogWindow('abc'); 
gdw.setTitle('Test'); 
gdw.setSize(750,300); 
gdw.setPreference('title', 'A New Title'); 
gdw.render();

Mark correct/helpful if it helps in solving your query

Thanks

Deepak