How to train my already trained model with a new class?

Question

Am kind of new to mxnet and I wanted to ask if I can execute a command to train my already trained model with a custom dataset. The first time I trained my model is i.e. with only one class ['dog'] then after I trained the model, I want to train it again with a new class of 'cat' so it will be like ['dog', 'cat']. Is this possible? Thanks in advance.