Yes of course...not to worry. In fact it is always best for your pup to be completely safe and comfortable.
I can always edit out the leash in post prossessing.
I highly recommend photographing outdoors in natural light at a park, beach or a pretty country side area. I can also come to your home or an area that you have in mind. We can discuss this further.
If the weather is not good for a session, we can reschedule.