Can a user enter expenses for 2 cost centers in one expense report

I have a user belonging to a dept for example 100. Now he will be doing some work for another dept, for example 200, so he will have expenses for this dept as well. My question is will he be able to enter expenses for dept 200 also on the same report as for 100?

The cost center currently defaults as 100 for him. I know he can change the department defaulting from 100 to 200 on the Expense Allocation page for the expenses incurred for dept 200. The approving manager is also the same for the 2 departments. Is this correct?

Thanks,