It is called being canonized or canonization
St. Petersburg is the name of a city and not a saint.
A person, or group of persons, petitions the Vatican to name a particular saint as a patron of a certain area of interest and presents the reasons. If the Vatican agrees, the person will then be declared a patron of that particular area.
There is no saint named Satna. Can you name the patron saint of poor spelling?
When a person enters a religious order they usually require that the person choose a new name to be used as a member. The name is usually that of a saint.
No, changing your name to that of a saint is a tradition in some religious orders, but it is not a formal requirement to become a nun or priest. Each religious community may have its own specific customs regarding names.
It is officially called Saint Lucia.
Which Saint Elizabeth were you referring to? There are many. We would need a specific name to give you a specific answer.
There is a Saint Alena but no Saint Aleena. Perhaps the name derives from Alena.
You choose a saint's name when you are baptized, and you may choose another saint's name when you are confirmed.
As far as I can determine, there is no canonized saint named Danielle. However, the name is derived from the name Daniel and there are many, many saints by that name.
You pick the name of a saint you wish to emulate or follow as a role model for your life.
Nicholas was the name given him by his parents.