Changing PAN, TAN, VAT, EC Code, CST, Service Tax No.

 Hi Experts,

Currently we are in the process of merging two OU's and two SOB's which were two different legal entities with different Tax registration numbers and continue to be till 31st July.

Client has got the court order for merger but they are in the process of obtaining the new PAN, TAN, VAT, EC Code & Service Tax nos. They will probably get these numbers only by Aug'15th. But they want to go-live on 1st Aug with old numbers and planning to replace the old numbers with new numbers after 15th Aug.

Though these fields are editable in the front-end (in Additional Org Info & in Regime Registration) we are not sure about the impacts if we change these numbers.