Gstr-3b missed b2b sales bill

Ambris Pande (Student) (160 Points)

16 January 2018  
If any firm missed some b2b bill in nov gstr-3b, can it be added to dec gstr-3b and pay the taxes ?
or wait for final gstr-3 and than pay the tax then only ?
If added in dec how it will be reconcilled for actual sales of nov nd dec ?