How to update schema and uiSchema in reactjsonschema form?

Question

I want to update schema and uiSchema on basis of the selection of options in the input dropdown. I want to add another key-value or may be more then one in both schema and uiSchema such as

schema:{
   properties:{
    a:{
    //details
   }
}
}

uiSchema:{
 a:{
 //details
 }
}

but when I select the option from the dropdown I want to update schema and uiSchema

schema:{
   properties:{
    a:{
    //details
   },
   b:{
    //details
   }
}
}

uiSchema:{
 a:{
 //details
 },
 b:{
    //details
   }
}

dropdown option may have multiple fields or widgets

is there any way to achieve this by using rules or any other option Thank you