Interacting with Objects - including weapon switching

It is an action to retrieve an item from your backpack or a bag of holding. If an item is stowed in your backpack it will take your action to get it out. If you identify the item as on your person it needs to be in a reasonable place. You can’t reasonably have 36 different weapons freely accessible at all times. But you can put your daggers in your boot, a sword in a sheath, a bow over your shoulder, a wand in your belt and a few potions tied to a leather sash you wear etc. Most of you have a 2nd or 3rd weapon handy, how is it handy? Be mindful that If it’s freely accessible and does not need an action, it can’t be in your bag of holding or backpack.

Generally speaking you can’t wear of the same type of item i.e. 2 hats, carry 2 shields, have 2 cloaks etc. You can’t wear 2 different types of armor but you can wear a cloak over your armor. If you have a hat of disguise and helm of comprehend languages, you won’t be able to don them both. You cannot don multiple bracers. You can however wear multiple rings. If you have a question please ask so you’re not surprised by a sudden ruling. Some exceptions that add color are fun to allow, like lucky wears a top hat on top of a pot on his head. It’s clearly visible and looks odd (plus there are no magical bonuses to that.) https://www.dndbeyond.com/sources/basic-rules/magic-items#MultipleItemsoftheSameKind

PHB: on your turn:

https://www.dndbeyond.com/sources/phb/combat#OtherActivityonYourTurn

… You can also interact with one object or feature of the environment for free, during either your move or your action. For example, you could open a door during your move as you stride toward a foe, or you could draw your weapon as part of the same action you use to attack. If you want to interact with a second object, you need to use your action…

DM Ruling

I’m sticking with the essence of this. If you have one weapon readied AND the other weapon is stowed on your person in a reasonable way, swapping to a 2nd weapon is no problem. But this must be done in 1 continuous and swift motion. I’m going to ask that you have pre-prepared this in some way that makes sense AND you describe this when you do it (add some flavor.) However, if you have 3 attacks, you can’t use 3 different weapons, only 2. Also if you swap from item 1 to item 2 you can’t swap back until your next turn.

If you choose to stow your weapon so you can perform a task, the stowing completes your free action. You can, on your next turn, as a free action draw the weapon. Also note: Interacting with an object usually requires a free hand.

This is important because there are some magic weapons that grant benefits only IF YOU ARE WEILDING IT. Please keep this in mind. If you get advantage or AC bonus or cold resistance if you are wielding the object and you swap to use a different object you will not regain those bonuses until you swap back on your next turn or unless you use action surge to use an action to swap back.

Not as part of a reaction

Unless you have a specific feat to allow you to do this, you cannot swap weapons as part of your reaction or opportunity attack.  See PHB quote above:  "during either your move or your action."
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