Im not sure about that since this website says that I can revert the situation
https://wowwiki.fandom.com/wiki/Blac...specialization
Changing specialties
Blacksmithing specialties could be changed at the trainers for a cost. The cost depended on the specialty you wish to drop and the character's level. Once you dropped a specialty, you could then choose a new specialty for no cost. Each specialty could only be dropped at the trainer that originally taught it. In order to switch from a Weaponsmithing subspecialty (Axesmithing for example) to Armorsmithing, you would first drop the Weaponsmithing subspecialty (should you have chosen one), then drop the Weaponsmithing specialty before you can learn Armorsmithing. Once you had earned either the Armorsmithing or Weaponsmithing specialty, you did not need to complete the quest line for the other specialty if you wish to switch. The specialty would be given at no cost.
Specialization benefits
"During the release of The Burning Crusade, you were able to learn any of the weapon subspecializations, by talking to one of the appropriate three masters in Everlook, and asking them to teach you (though you must still have completed the weaponsmithing quest, as above). The quests, however, rewarded the same plans. These abilities can be unlearned for 100Gold and another weapon subspecialization can be learned in their place."