ENS App and Explorer are on the Sepolia testnet. Features may change before mainnet.
A resolver is a contract on the Ethereum network that answers questions about your name, such as which address it points to. Registering sets a default one for you, so most people never change it.
Good to know
The main reason to change it: your names share one resolver, so anyone you give record access reaches all of them. A name on its own resolver keeps its access separate. See Why do all my names share one resolver?
You need to be connected with the wallet that owns the name, or one that holds the Set Resolver role on it, with a little ETH for gas. Gas is the network fee; your wallet shows it before you approve.
Your records are stored on the resolver. Switching to a different resolver changes which records your name reads.
Change the resolver
Open the name in ENS Explorer and select the Resolver tab.
Select Change resolver. If you cannot see it, you are not connected with the wallet that owns the name or one that holds its Set Resolver role, or the name has no resolver at all (possible if its resolver was removed).
Pick one of the three options (explained next). If in doubt, deploy a new permissioned resolver.
Select Save Changes and approve in your wallet. If you deploy a new resolver, your wallet asks you first to deploy it, then to point your name at it.
Check the Resolver tab. Once the transactions confirm, it shows the resolver's details, and you can edit records on the Records tab.
The three options
Deploy new permissioned resolver: the safe default, and the one almost everyone picks. Leave Use custom resolver off. Explorer creates another copy of the resolver ENS provides (the public resolver), whose code has been independently checked, and points this name at it. Your wallet is its only role holder to start with. Permissioned means roles are built in: you can let another wallet edit particular records without handing over the name.
Use custom resolver: paste any contract address. Use this only when you know and trust the resolver at that address.
Existing permissioned resolver: pick one you deployed before. If the list will not load, deploy a new one instead.
Important: Explorer does not check that a custom address is a real resolver. Paste the wrong thing and your name stops resolving, with no error to warn you. Check the address before you save.
Check a custom resolver first
A custom resolver can be a real, working contract and still not handle every kind of record. Then most of your records keep working and only the unsupported ones stop, with nothing to tell you. Before you switch, open that resolver's own page in ENS Explorer (its address links straight there) and read the Interfaces list: the record types it supports. If a record type you need is not on it, that record stops resolving the moment you switch.
Common questions
How long does it take?
Each transaction usually confirms within a minute on a quiet network; a busy network takes longer. The Transaction Manager shows progress. See How does the Transaction Manager work in ENS Explorer?
Can I undo a resolver change?
Yes. Open Change resolver again and set it back. The records on the previous resolver are still stored there; they just were not being read. Switching back restores them, unless someone with a role on that resolver changed them in the meantime. Check your records after any change.
Will names I register later use the new resolver?
No. Names you register in the ENS App still use the resolver set up with your first name. Change each one here if you want it elsewhere.
The change confirmed, but my name stopped resolving
Two things do this. Either the address you pasted is not a working resolver, or it is a working resolver with no records on it — a fresh resolver starts empty, so the name answers nothing until you set the records again. Open the Records tab and check. If the records are there and the name still does not resolve, open Change resolver again and deploy a new permissioned resolver, or paste an address you trust. See What do I do when a transaction goes wrong in ENS Explorer?