How To Switch From Eliquis To Pradaxa?

My Husband has a pacemaker since 9/7/2004. He has ongoing bouts of AF. He has been on Eliquis since 11/19/ 2014. He's having some bleeding side effects and Dr wants to put him back Pradaxa. He was on Pradaxa from 2/24/2012 to 11/4/2013. He was cardioverted to sinus rhythm on 5/16/20/2013. His AF started again in July, 2014. My question is, what is the best way to change him from the eliquis to Pradaxa?