Playing an event without valid target(s)?

[Fromper 44]

I have questions about a couple of events. Generally speaking, can you play an event, even if you can't do exactly what it says?

For instance, Rise Again says to heal 5 damage to a character, but not "up to 5". So if the only unique blue character you could play it on only has 4 damage, does that mean you can't play it?

Similarly, Triple Threat says to reroll 3 character dice. What if there are only 2 character dice in both players' pools? Does that mean the card isn't playable at that time?

[DarkFallenAngel 8]

The rule is do as much as you can. So you can play Rise Again when fully health for example and attach an upgrade from the discard.  The very important caveat here is that is a card says THEN you can only do the part after then if ALL the first part is done. 

[Fromper 44]

That's good information.

I actually checked the Rules Reference, and found the answer to my follow up question. Rise Again says to heal 5 damage, rather than "up to 5 damage", so I was going to ask if it can be used on a character with only 4 damage. According to page 20 of the latest Rules Reference, "Heal as much damage as possible. Excess healing is ignored." So the answer is that yes, you can heal anywhere from 1 to 5 points of healing with it, which I wanted to know.

I don't think that works for Triple Threat, though. I think there do have to be 3 character dice in both players' pools to get any use out of that one. 

[DarkFallenAngel 8]

You can use Triple Threat with less than three character dice in the pool and roll as many as there. If there are three or more you have to roll three. If you do not roll three as the next part is a THEN you can’t do the turn a die part