You can import your Legacy RefWorks database into the New RefWorks account whenever you like. ! References/folders/output styles do not disappear from the Legacy RefWorks, instead they will be copied into the New RefWorks.
Before implementing the New RefWorks you should take into account that
OPTION 1) USE "IMPORT REFERENCES" TOOL IN THE NEW REFWORKS
You can import the references and the attachments from the Legacy RefWorks account into the New RefWorks account by using an Import references tool (! if you have several attachments within one reference, the reference will be imported into the New RefWorks as many times as many attachments you have). You're folders and output styles will be imported into New RefWorks also. ! References/folders/output styles do not disappear from the Legacy RefWorks, instead they will be copied into the New RefWorks.
1. Log in to the New RefWorks -> Add -> Import References.
2. Import from another reference manager -> RefWorks
3. Authenticate the import with RefWorks by clicking Authorize.
4. After clicking the button log in to your Legacy RefWorks account
5. You will get a message if some references/folders/output styles haven't been imported.
6. Click OK. You will see the references in the Last Imported folder.
7. You can import your references into the New RefWorks several times (e.g. if you want to use both Legacy and New RefWorks). References imported to the New RefWorks can't be imported to Legacy RefWorks.
OPTION 2) USE "SOFT MIGRATION" TOOL IN LEGACY REFWORKS
Click on the icon on the top left in your old RefWorks.
Reference: Uusi RefWorks: Siirtyminen vanhasta uuteen RefWorksiin, Tampereen yliopiston kirjasto, web page. Available (retrieved 23.8.2016): http://libguides.uta.fi/uusirefworksopas/siirtyminen.