Hi Jennifer,
I recently came out at work and although you cannot possibly judge how people will react you have to go on the assumption that your colleagues will be professional and helpful. i was petrified as i was so worried about my staff reaction. i, too, am a line manager and i found that telling each member of my team, before i took leave to begin my transition, was the best policy for me. i had and still have the support of my manager and my company and by being honest and open with my team meant i didn't have to hide anything. i wrote a letter to the support staff in my branch, detailing my decision and my future. i was honest, open and also frank in explaining what i was going through, what i would be going through and also what i expected from them. Any discrimination would be dealt with by the company but that cautionary note aside i kept it light and to the point. i have had no trouble from staff or customers and i am so happy to finally be myself. My advice would be just be you. Be a better person and enjoy your transition. Find out from your HR team what you need to do regarding payroll changes and the like.
Everyones circumstances are different. things that worked for me may not work for you but i found being honest, open and as helpful as i could be meant people treat me with respect. we can't control how people react or behave but we can handle our own behaviour. Best of luck and always try to be positive.

Faye.