Does the Shifting rune change damage dice and weapon traits?

I'm playing a fighter in book 2 of Age of Ashes and the party just got a +1 Striking Shifting Cold Iron Dagger. I'm little confused about how exactly this works. From the text of the rune: "The weapon takes the shape of another melee weapon that requires the same number of hands to wield. The weapon's runes and any precious material it's made of apply to the weapon's new shape."

So theoretically, let's say I transform this dagger into a whip. Does it then lose the agile, thrown, and versatile traits from being a dagger and then gain disarm, nonlethal, reach and trip from being a whip now?

Similarly, what if I change it to a flail? Does the damage change from 1d4 P to 1d6 B?

I guess what I'm confused on is whether the Shifting rune purely changes appearance or if it actually grants the properties of the new weapon?

Yes, it changes everything. Dice, properties, the whole shebang.

It is limited to only one-handed weapons since it's a dagger, and you use your Proficiency with whatever weapon it currently is, but aside from that the sky's the limit.

Is there an official Paizo ruling on that? It feels like that's the obvious way the rune works but I'm curious if they've weighed in.

No.

There isn't much need for one, either.

ShiftingItem 6

MagicalTransmutation
Source Core Rulebook pg. 585 1.1
Price 225 gp
Usage etched onto a melee weapon
With a moment of manipulation, you can shift this weapon into a different weapon with a similar form.

Activate Single Action Interact; Effect The weapon takes the shape of another melee weapon that requires the same number of hands to wield. The weapon’s runes and any precious material it’s made of apply to the weapon’s new shape. Any property runes that can’t apply to the new form are suppressed until the item takes a shape to which they can apply.

If the change was only cosmetic and didn't change the function of the weapon, then what property runes could apply also wouldn't change.

Is there an official Paizo ruling on that? It feels like that's the obvious way the rune works but I'm curious if they've weighed in.

They really don't need to. The item includes the following text:

"Any property runes that can’t apply to the new form are suppressed until the item takes a shape to which they can apply."

Which doesn't even make sense if the stats don't change.

It also says:

"With a moment of manipulation, you can shift this weapon into a different weapon with a similar form."

Note 'into a different weapon' not 'into the appearance of a different weapon'. I can see how the later text about 'the shape' could make you doubt, but as near as I can tell you're literally the first person who's ever posted a doubt that it can actually transform the weapon's stats. There is basically complete consensus on what this means.

EDIT: Ninja'd. Ah, well.

While I agree with Deadmanwalking on how the Shifting Rune works, trying to transform a cold iron dagger into a whip is a bit 'fuzzy' since there are no rules so far about precious material, non-metal, non-wood, weapons (Whips are described as 'long strand of thick leather, often braided'):

• On the one hand, the rune distinctly states you keep the precious material
• On the other hand, Cold Iron whips aren't 'legal' weapons and don't really make a lot of sense.

Source Core Rulebook pg. 599 1.1

Weapons made of precious materials are more expensive and sometimes have special effects. You can make metal weapons out of any of these materials except darkwood, and wooden weapons out of darkwood. To determine the Price of 10 pieces of ammunition, use the base Price for a single weapon, without adding any extra for Bulk.

Generally speaking, the 'specific (rune) rule trumps general (precious material weapon) rule' logic probably applies here and you can end up with a cold iron whip or Darkwood longsword (hey, it's magic), but I can see GMs possibly having issues with combinations like these.

The other question on the shifting rune that came up fairly recently was if the transformation is truly permanent: If the rune is removed, does the weapon revert to its original form or does it stay in its current form forever? Personally, I think it should revert (mainly to avoid Doubling Ring shenanigans), but I don't believe there is a clear answer one way or another.

That's fair. A flail would definitely work, though, and a scorpion whip probably would, too (those have metal blades, after all) even if whip is more ambiguous.

It wasn't my intention to claim that there were no ambiguities in how to handle the Shifting Rune, as there clearly are (how you handle putting it on a magic staff like a staff of healing, for example), just to clarify that there is widespread agreement about the basic way it functions (ie: changes damage dice and traits).

If it only changed appearance, virtually no one would spend 225 gp on it.

I'm also playing a fighter in Age of Ashes, and that weapon has been INCREDIBLY useful. Just remember it's limited to taking the shape of a one-handed weapon. But besides that, it only takes 1 action to have a relevant weapon in your hand:
- I usually keep it in gauntlet form; that way I don't have to waste an action drawing it if I need it (also enhances my attacks when I just need to punch someone).
- Sap when we needed to capture someone.
- Hatchet to cut my way through a wooden cage.
- Dwarven war axe to cut down large poles.
- As a decoy for thieves looking for an important exotic weapon we had found.