Thank's to cHao the answer is found.

On the Main Form that you want to branch out from, add this to your buttons event handler (The Word Custom should be replaced with the form you wish to go to.)
Custom^ newForm = gcnew Custom();

this->Hide();

newForm->ShowDialog();

this->Show();

delete newForm;

`

And on the subform you should include this line in another buttons event handler (I am using it in a back button.) This returns you back to the original form.
this->DialogResult = System::Windows::Forms::DialogResult::OK;