Communicate between View Models in MVVM

I am using MVVM pattern in my project. Here is the pseudo code.

class ViewModelA {
     propertyA;
     methodA(); // updates propertyA
}

class ViewModelB {
     methodB() {
     // update properties of ViewModelB
     // Needs to update propertyA of ViewModelA
     }
}

I have two view models ViewModelA and ViewModelB. MethodB of ViewModelB needs to update propertyA of ViewModelA.

I can keep a reference of an instance of ViewModelA inside ViewModelB and call methodA to update propertyA of ViewModelA. Is it a good practice to keep a reference of one view model inside another view model in MVVM pattern? Also, would like to know other ways in which View models can update properties of other view models.