managing positions in org management

Hello Team,

What is the best way to manage scenarios where there is an overlap in the time between an employee leaving and a new employee starting in the same position.

e.g. Employee one is leaving on May 31, 2010 and employee two is starting in that position on May 14, 2010 to train with the leaving employee. I don't want two people in the same position and I don't want extra positions to affect my headcount and budget etc.

Thanks in advance for your help.

Regards,

Jeanette