Update favicon without delete entry?

Hello,
How can I update a website favicon without delete the entry (contains a lots a custom fields).

Thank you !

Let’s assume that an item already has 3 existing URLs A, B and C:

A
B
C

As the URL A is on top its icon is shown.

The new URL X contains the new favorite icon. So you add it at the bottom of that list:

A
B
C
X

Make a copy of the top URL A and add it as the 5th URL:

A
B
C
X
A (copy)

Delete the top URL A:

B
C
X
A (copy)

Repeat the procedure mentioned above till the URL X is on top:

B
C
X
A (copy)
B (copy)

C
X
A (copy)
B (copy)

C
X
A (copy)
B (copy)
C (copy)

X
A (copy)
B (copy)
C (copy)

Done! From now on the icon from the URL X is shown.