Re-Baseline with actual progress

go into S2 and make S1 as a baseline then go to maintian baslines and then select update and choose what you want to update from S2 into S1

Submitting S2 as a Re-Baseline-002 is an acceptable practice.

Having said that if the shedule is resource loaded and you are doing EV, PV etc out of schedule then it will be somewhat different procedure.

I would like to say that: 

S1 is my initial planning and let's say S11 is the update of S1 on 25/02/2020.

S2 = S1+new WBS and new tasks

how to import the S11 (the update version) into S2?

I do not understand why you need to importthe S1 in S2 with the updated tasks

because you said

 (S2 = S1 + new tasks) 

The tasks are already in there 

Hello,

I have my initial schedule (S1), I updated this schedule on February 25.

In the meantime, I created a new schedule (S2 = S1 + new tasks) by adding new tasks and WBS, how to make this S2 as baseline for my previous schedule and maintain the progress of S1?

How to import the S1 in S2 with the updated tasks?

Regards

Fouad

http://www.planningplanet.com/blog/baseline-change-management

Be reminded that by making the updated schedule version the new baseline all variance is erased.  Needless to say this new updated schedule must meet current contract conditions and milestones.

• I favor making updated schedule equal to your new baseline rather than using the other complicated alternate procedures equally acceptable to the DOD. 
• Errors can be avoided if you look at prior versions to look at variance against prior baselines rather than implementing the cumbersome alternate procedures.

you can NOT remove the actulas they are a permanent recored of what happend when on the project. 

Recschedule your project from this point forward adjusting durations and andy sequences make sure that after you schedule the project that your completion date is on or before the contractual completion date. 

This is the revised basleine schedule.

What do you mean by "is it allowable" , your first recourse is to understand what your own contract specifies in regards to this.

you must re-basline with actuals this is your new line in the sand