Within Teamwork Chat, you can reset your password via the web version of the app.
On the login screen, select Forgot password from the password field.
You will then be prompted to enter an email address to receive your password reset on.
Once the email has been received, click the link as directed by the email. You will then be prompted to create a new password for your account.
Note: Changing your password from Teamwork Chat will also update the password for all Teamwork products associated with that account.
For more information see: Accessing Your Teamwork Chat Site