Use the Assume option on the user who should take over. It moves every record the old user created or owns, and every action assigned to them, in one step.

Note: Applies to: system administrators (admin role).

Steps #

1. Click the Set up spanner at the bottom left, then select Users.
2. Click the user who will take over the records.
3. Click the three dots (⋮) at the top right and select Assume….

4. In Assume Ownership Of, pick the user being replaced, then click Give Ownership and confirm.

Critical: All ownership moves from the selected user, including records they created and actions assigned to them. Do this before you delete a user, because deleting them first leaves their records without an owner.

The full walkthrough is in Transferring Ownership from One User to Another (Assuming).