Ca and cs - can we practice both?

I think we can practice both CA and CS. can have COP(Certificate of Practice) of both Institutes subject to permission. but can't use both designations simultaneously.

For matters of Audit, Taxation,etc  matters like that only CA can certify u should only use Chartered Accountant as designation and for matters in which only a Company Secretary can deal you can use designation as Company secretary only.You are not allowed to use both designations simultaneously.

this is mentioned in Chartered Accountants Act. don't know about practical aspects. you can wait for Expert opinions..

No. Only one practice is allowed