lavone243 wrote:
Please help me delete Mac account on my iPhone Generation 2 and upgrade it to Generation 3
You’ll need the Apple ID and password associated with Activation Lock to prepare an iPhone for use, or for sale.
What to do before you sell, give away, or trade in your iPhone or iPad - Apple Support
Activation Lock is intended as a theft deterrent, so it is intentionally difficult to bypass. We can’t help, and absent convincing proof of ownership Apple won’t.
If a seller has provided you with a device locked to an Apple ID, contact the seller and request they perform the above-lined procedure, or refund your purchase.
If the seller has disappeared and you have an iPhone locked to an Apple ID not yours, you got scammed. Recycle it. The iPhone will never be useful without the Apple ID holding the Activation Lock lock, or without evidence of ownership sufficient to convince Apple to release the lock such as the original purchase receipt from Apple or an authorized reseller.
As indicated in another reply of mine in this thread, there is no means to upgrade iPhone hardware short of replacement.