I was just flipping through some of the melee action cards, and I read over the text of Duelist's Strike. The 1 Boon effect confuses me a little. It says "You may move your engagement to another location within close range." Using the card requires that you are only engaged with the target and no one else. Does this effect basically mean that you can force your target to move, but you also move with him?

Yes.

...........

That's what the card does. While that may not seem like a huge benefit it can be strategic. First if you use lots of location cards you could use this card to move the engagement to a more favorable location. The more strategic element is in using this card to push the engagement closer to a companion of yours which would then allow that companion to possibly get in on the action using less movement manoeuvers or moving you out of range from other opponents making it harder for them to get to you.

It's not a very powerful card but it can be highly effective in the right situation. It's one of those smart/agile fighter cards.

Okay. This is what I thought the card did, but I also thought it was possible to read it as changing from being engaged with one character to being engaged with another, and it's in my nature, generally, to double-check any bits of rules-text I'm even slightly unsure on.

You need to think like a Swashbuckler to use this card. You don't just stand and fight. One guy has some sort of edge, drives the other up the stairs, where the other guy gets an edge, driving them back down, where the first jumps on a table, up the stairs again, across the balcony, swing a chandelier, etc.