Reported iPhone lost but now found

It all depends on what you did when / if you reported the phone as Lost.

If you enabled Lost Mode on the phone using Find My you can remove that setting by logging on again.

If you reported to your carrier that the phone was lost, you would need to notify them that the phone is no longer lost

If you notified your bank or other financial institution that the phone was lost, you would need to update with the bank, etc.

I think you get the idea.

Who did you report it to as lost?