How I can switch between environements on Conda Kaggle?

I am using the Kaggle platform to train a Deep Learning model, I can't figure out how I can deactivate the base environement and activate another environement, for example : tensorflow115. I tried the conda deactivate base/source deactivate base command then conda activate tensorflow115/source activate tensorflow115 without any effect. How I can resolve this problem ?

# conda environments:
#
base * /opt/conda
tensorflow115 /opt/conda/envs/tensorflow115

Note: you may need to restart the kernel to use updated packages.