The answer is easy.... but you end up with CO2 again. Just heat it. If it is in an aqueous form, you need to dry it first then heat it.

Heat the solution of Na2CO3 to bubble off the CO2 by boiling the solution and you will get NaOH as a result.

then how high the temperature ? and how long the process until i get the pure NaOH again ?

I think it will need more energy to release CO2 than to capture it, because naturally NaOH capture CO2. If you want to make it back to solid form NaOH, maybe you can try to heated more than boiling water temperature, but if you only need to make it back to NaOH solution, maybe 60-80 C is enough. I suggest you to try it or find suitable reference related CO2 release from Na2CO3.

Sodium carbonate (washing soda) is Na2CO3 is a very stable carbonate, resisting decomposition upto a very high temperature, often till its melting temperature

. When it is heated it undergoes a thermal decomposition reaction. This takes place above 500 degree C (approx).

Na2CO3 (s) = Na2O (s) + CO2 (g)

Na2O is Sodium Oxide which is solid and used in glass making Use of a vacuum pump to suck out the gas eases the decomposition reaction.

As Rishi stated above, I have not heard of doing this in solution, but it may be possible. For conversion of CaCO3 (Calcium Carbonate) to CaO (lime) commercially, it is done in high temperature rotary cement kilns.

thank you very much for all the comment about my problem, recently i try to use membrane electrolysis to solve my regeneration problem

You can heat up about 105 C and after evaporation of water and cooling, the crystals of Na2CO3 is formed. Moreover, you can add some Ca(OH)2 to change into NaOH easily. na2co3+ca(oh)2=naoh+caco3 in which, CaCO3 is sediment.