I am starting a new job. It had been my understanding that each piece of paper work required would take at least 5 days to process. This gave me expectations as to what the start date would be. I submitted some paper work yesterday to get a message today saying I have training scheduled for tomorrow. Due to other commitments, including my previous job, I cannot start tomorrow. I can take a day off the following day, and officially begin the next week. How can I tactfully convey this to my new manager? I hate to get off to a rough start.
Is this best done through email or a phone call?