If I read this correctly, your managers' contact data are listed in the employee table along with your employees (as should be the case here) and when you select a manager in the manager name field, you want the manager's contact info to appear automatically.
I'd match records by your employee ID field, not the manager's name. One of your managers might just change their name after all and then you have problem updating the name without breaking links to other related records such as these.
Here's a thread that describes two methods for doing what you want. I think you'll find that the dynamic link option is the better one in your situation: Auto Fill
Thanks it resolved my problem, I used option 1 in your provided link.
Thanks Phill :)