Reassigning activities - please help

Hello everyone,

I am fairly new in working with sap and therefore have the following question. I have 300 activities/calls assigned to a person. This person has left my company. I now want to reassign the activities to his replacement. In other words, the person who left the company needs to be replaced by a new name. Can the activities be reassigned all at once instead of changing the name one by one for each activity?

Thx!

Bart