How to increase the memory size of stack and heap in Coretx-R8

In the default examples available under ARM Development Studio 2019.1 release version I have picked up startup_Cortex-R8 example.

The default memory configuration details in the scatter file for Cortex-R8 is shown below, but I want to increase the memory size of stack and heap from 16 KB to 1MB.

How can we do this?

Can you please share us more details/steps to make this changes.

Thanks.