If you copied your account data from one Stripe account to another and need to recreate the subscriptions and plans in your old account:
Recreate your products and plans on the new account. This can be done in the Dashboard or using the Stripe API. When recreating the plans, specify the same id for each plan as on your former account.
Add subscriptions to your copied-over customers on the new account. Customers that were copied over will have the same customer ID as in the original account.
If you want to use the same billing dates on the new account as you did on the old account, you can force the billing period of subscriptions on the new account by setting a custom trial end date when you create them.