Can I Bind an EIP of an ECS to Another ECS?

Yes.

You can unbind the EIP from the original ECS. For details, see Unbinding an EIP from an Instance.

Then, bind the EIP to the target ECS. For details, see Binding an EIP to an Instancesection "Assigning an EIP and Binding It to an ECS" in Elastic IP User Guide.

If you want to change an EIP for your ECS, refer to Changing an EIP.