You can copy a set of baseline or interim plan values from one baseline\interim plan to another. This is useful when you decide that you really do need to overwrite the main Baseline. By copying the Baseline values into one of the Baseline1 “Baseline10 baselines, you retain the original values of the Baseline, and can then overwrite it knowing you can still access the old values. This section will also cover how to clear a baseline, which means to remove all the data from a given baseline.
Copying Between Baselines
Click the Tools, Tracking, Save Baseline menu item.
Select Save Interim Plan.
In the Copy field, select the base line you want to make a copy of.
In the Into field, select the Baseline that should have the From baseline values copied into it.
Click OK.
Clearing (Deleting) Baselines
Click the Tools, Tracking, Clear Baselines menu item.
Choose whether you want to clear a baseline plan or an interim plan.
Select the baseline or interim plan you want to clear.
Select whether you want to clear the entire project or just the selected tasks .
Click the Tools, Tracking, Save Baseline menu item. 
Select Save Interim Plan. 
In the Copy field, select the base line you want to make a copy of. 
In the Into field, select the Baseline that should have the From baseline values copied into it. 
Click OK. 
