The Ranger card and Monster Taming.
 

The Ranger's "Monster Tamer" text has you discard your current printed Steed, if in use, as part of the ability to tame a new one. If you want to replace that Monster (now converted to a steed) at all, do I have the option to do so, may I in fact never do so until I have to discard any card of choice by some means from another card?

Re: The Ranger card and Monster Taming.
 

As was stated in the other thread/s, you could (and in fact must) discard the tamed Steed to tame a new Steed via the Monster Tamer ability. Other than that, there is no easy way to get rid of the tamed Steed, except for cards that would allow you to discard a Steed or discard a card.