Need to move installment plan to another number on the same account

I have two phones on my account.  Samsung Note 20 (phone 111-111-1111) and Iphone 13 pro max (phone 222-222-2222).  The samsung is free and clear but the apple has installments.  I switched the phone numbers thinking I could cancel one later but was told that the installment is on the Line not the phone.  so now the apple is listed as free and clear and the samsung has payments because it has the old phone number that initiated the installment agreement.

now the apple is on 111-111-1111 and samsung on 222-222-2222.  and 222-222-2222 has the installments.  I need to keep 111-111-1111 and dont have need for 222-222-2222.  Need a way to drop 222-222-2222, by moving it to 111-111-1111, upgrading 222-222-2222 and in process change number or some kind of transfer so I get out of the deal with

111-111-1111 having an installment - either the existing one or even a new one and

222-222-2222 being free and clear (or off because once it is free and clear I plan to cancel it anyway)

Anybody got any ideas