Here's how to manage your call history in the 2nd Phone Number app:
Deleting a Single Contact:
Open the 2nd Phone Number app.
Go to the "Recents" tab to see your call history.
Find the contact you want to remove.
Swipe left on the contact's entry. This will reveal options.
Tap "Delete".
Confirm by tapping "OK" to remove the contact from your call history.
Bonus Tip: You can also search for specific contacts or numbers in your call history using the search bar. Then, you can delete them individually using the same method for deleting a single contact.
Important Note: Once you delete calls or contacts from your history, they cannot be recovered. Make sure you're sure before confirming the deletion.