Is your feature request related to a problem? Please describe.
Any vault that provides unused mint capacity is subject to the ‘risk’ of receiving an issue request that can fill up all its remaining mint capacity. Hence, a replace request by another vault is nothing else than an issue request by a user (and hence should charge the same fees) but helps vaults at risk to mitigate liquidations.

Describe the solution you'd like
If a vault can request a replace by another vault with certainty, there is much lower risk of getting liquidated. If the vault which is supposed to replace the original vault has an option to decline this request, that option of risk mitigation becomes quite meaningless.

Additional context
We can achieve this functionality without changing too much in the replace core model.

• As is: oldVault announces to want to replace X BTC
• Changed: oldVault can accept replace request on behalf of newVault (similar to how on issue the vault is not involved but rather the user makes the request and the vault cannot decline)
• As is: execution of the request.