When your company changes from Sole trader to a limited company or vice versa, we recommend that you open a new KashFlow account for your limited company to keep everything separate.
Then you can export suppliers and customers from your sole trader account by going to Reports> General Reports> Sage Export.
You can request the CSV mapping files for suppliers here, and customers here, and you can map the sage export CSV to the correct format to import into the new account. Then you can login to your limited company account and go to Settings> import data> CSV and import your data.
Once you have finished using the original Sole trader database, you can stop your subscription for this by going to Settings> Manage Subscription and select to cancel the subscription. Once you have done this you will no longer have access to the data. If you wish to keep the information from this database you will need to print off the information you wish to keep prior to cancelling the subscription.