Blueprints that remove red/green wires

[Illiander42]

Simple request given recent FFF:

When pasting blueprints of combinators over existing stuff, the blueprints do not remove existing wires. Give us a way to say "replace red/green/copper wires instead of adding to them."

The practical example I can think of is switching an LTN station from provide to request. But any general upgrade of circuits will potentially have issues with this.