Sure, you can simply move one or more leads across your lists in the Leads section of your account in a few clicks.
To do so, while on the original leads list, select the leads you would like to move. If you wish to move all of the leads inside your leads list, don't select any specific leads. This will automatically select them all.
Click on the Actions button and then on the Move to a list button;
A popup page will appear. Select the destination list and confirm the change by clicking Move leads.
💡 Note: To move a lead, you need to be inside a specific list rather than on the "All leads" page.
How to merge leads
You can also move an entire list of leads and merge it with another list by using the "Merge with another list" option:
Click on the arrow next to your list's name;
Click on ''Merge with another list'';
A popup page will show up to select the ''Destination list''. After selecting it, click on ''Merge lists''.
For more details, you can read the section about lead verifications in this leads help article.