Hi everyone...
Need a 4000 mA battery...
Can I substitute it with two 2200mA batteries in parallel ?

Sure you can.. make sure both are of same discharge rating and also while connecting both the cells should be balanced evenly as much as possible..

Thanks for the reply...  Just one more thing will that dictate the terms for using an higher rated ESC

The amount of Amps that the Paralleled LiPo's in this case is able to deliver will be double than that in case of singles.
But that doesn't mean that you will have to use a higher Amp rated ESC for it.

Amp rating of the ESC will be determined by your motor and it doesn't changes with paralleling LiPo's.

It's the motor that decides how much amps it will require, based you which you choose the compatible ESC.

Thanks for the input....