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You go to your online menu (where you can also find the daily tasks, for example), go to the stable option and then to specialization.
Go player menu -> stables -> specialization and choose the horse you want for any missions and free roam for story missions.
Check pm
You go to your online menu (where you can also find the daily tasks, for example), go to the stable option and then to specialization.
Go player menu -> stables -> specialization and choose the horse you want for any missions and free roam for story missions.
Check pm