Office 2010 Home & Business Key Swap

[Pigeon_Killer]

I've got two retail copies of Office 2010 H&B installed on two PCs at work. I installed one of those copies in January and now the user has decided they would like Publisher. Ordinarily this would mean purchasing a Pro license or a standalone copy of Publisher but MS have an offer on at the moment that allows you to download Publisher for free if Office was/is activated between February 8th and March 21st.

The other copy I mentioned was activated during the offer period so can I simply switch the keys?

Thanks