Hi Malik,

Im sorry but i could not much from your question, but I suppose what you mean to ask is what is " Maintain Baseline" and what is "Assign Baseline".

If thats what you meant,lets say that you have created a schedule for a Project and you have reached a stage where you feel that you will will freeze the program and compare your progress against it. So you decide to set that schedule as a baseline for comparison in the future. This is done by using the "Maintain Baseline". 

Then lets say you feel that there is another change that you want to make to the schedule and would want to have another baseline set which includes this change, and you would want to compare your progress against this second baseline if required. So you use the "Maintain Baseline" to set another baseline. You can have multiple such baselines against which yuo may want to compare your Project progress.

Using the "Assign Baseline" what you are doing is defining which of these baselines you would like to compare the progress to. Normally you have one baseline based on Contractual Dates, and you can have other baselines created based on a certain assumption. If the assumption takes form you have the option to "Assign Baseline" which you had "Maintained" on the basis of this assumption and then compare your progress to this Baseline.

Hope this answers your question, if that was what the question meant.

Regards,

Abdullah Merchant.