Eldritch Cannon - can I change type simply by expending a spell slot as a free action

[pantastic]

What do I have to do to change my Eldritch Cannon (ability of Artificer class, subclass Artillerist) from one type to another (assuming I can't take a long rest to do it)?

http://dnd5e.wikidot.com/artificer says:

"Once you create a cannon, you can't do so again until you finish a long rest. or until you expend a spell slot of 1st level or higher."

When you create the EC, you can choose one of three types (flames, force, or healing). If I create it as a force cannon, and then want to switch it to healing, do I expend a spell slot, but not cast the spell? Is there an action I missed somewhere, or is changing it a free action?

The full text from the website, copied and pasted, is:

At 3rd level, you learn how to create a magical cannon. Using woodcarver's tools or smith's tools, you can take an action to magically create a Small or Tiny eldritch cannon in an unoccupied space on a horizontal surface within 5 feet of you. A Small eldritch cannon occupies its space, and a Tiny one can be held in one hand.

Once you create a cannon, you can't do so again until you finish a long rest. or until you expend a spell slot of 1st level or higher. You can have only one cannon at a time and can't create one while your cannon is present. The cannon is a magical object. Regardless of size, the cannon has an AC of 18 and a number of hit points equal to five times your artificer level. It is immune to poison damage, psychic damage, and all conditions. If it is forced to make an ability check or saving throw, treat all it's ability scores as 10 (+0). If the Mending spell is cast on it, it regains 2d6 hit points. It disappears if it is reduced to 0 hit points or after 1 hour. You can dismiss it early as an action.

When you create the cannon, you determine its appearance and whether it has legs. You also decide which type it is, choosing from the options on the Eldritch Cannon table. On each of your turns, you can take a bonus action to cause the cannon to activate if you are within 60 feet of it. As part of the same bonus action, you can direct the cannon to walk or climb up to 15 feet to an unoccupied space, provided it has legs.

It then lists the three types of cannon (Flamethrower, Force Ballista, and Protector).

Thanks in advance!

[Nagog]

I would rule it takes an action to do, and it expends the slot, as essentially you are deconstructing the old one and rebuilding it as the new type thematically, while mechanically you're making a new one and the old one disappears.

[JackPhoenix]

Here: "Using woodcarver's tools or smith's tools, you can take an action to magically create a Small or Tiny eldritch cannon in an unoccupied space on a horizontal surface within 5 feet of you."

You aren't switching what the cannon does, you're creating a new one, with all the requirements it had normally.

[Eriol]

Unfortunately for you, I would rule RAW that you need two actions to switch it. Focus in on these two lines of the text you posted above:

Once you create a cannon, you can't do so again until you finish a long rest. or until you expend a spell slot of 1st level or higher. You can have only one cannon at a time and can't create one while your cannon is present.

You can dismiss it early as an action.
So if you have a cannon out, you have to use an action to dismiss it, and then next turn (barring Action Surge, which is possible, but unlikely) as your action you can expend a spell slot to make a new one of whatever type, following the regular rules. So I think that's the RAW answer about changing the type.

If I were DMing the game though, I'd rule you can do both in the same action. Same resource usage, but less clunky with taking two full rounds. But that's not Rules As Written (RAW), that's Rules as Fun, so ask your DM. They may agree that it's too clunky as it is.

[pantastic]

Unfortunately for you, I would rule RAW that you need two actions to switch it ...

That makes sense to me. Thanks everybody for the help.

[Misterwhisper]

That makes sense to me. Thanks everybody for the help.

Actually you can just create the second one, as soon as you do the first will disappear because you can only have one.

[pantastic]

Actually you can just create the second one, as soon as you do the first will disappear because you can only have one.

Actual text seems to say:

You can have only one cannon at a time and can't create one while your cannon is present.