1) You have to go to CAS database = Charles University Authentication Service

link

2) You will put there your e-mail from SIS or fill your First Name, Last Name, Date of birth

3) You will see a second tab in which you should fill also your

a) PERSONAL NUMBER - you can find it on your ISIC card beneath your picture

b) ID CARD NUMBER     -  big letters in the white rectangle at the bottom of the ISIC card

c) BIRTH CODE SUFFIX -  usually it is 11X9. If it doesn't work try 11X8, 11X7,... 

If it still doesn't work please contact student office.

d) Submit.

4) You will get on your e-mail special code which you will copy to the 3rd tab.

You will also fill your new password and repeat it in the next line.

Submit.

5) Your new password is set.