Learn Spanish (Latin America): Con permiso, señora.

In Spanish, the phrase you use for "excuse me" depends on the situation. Con permiso (literally "with permission") is used when you need someone to move so you can pass by, or when you are politely leaving a room. If you bumped into the lady or needed to get her attention to ask a question, you would use disculpe or perdón.

I thought señora meant "Mrs.". Can it also mean "ma'am"?

Yes! When you are talking directly to an adult woman you don't know well, señora is used as a polite sign of respect, exactly like "ma'am" in English. If you were talking about her instead of to her, you would use it like "Mrs." alongside her last name (for example, la señora García).

How does this sentence relate to the formal usted and informal tú?

Calling someone señora immediately sets a formal, respectful tone. Even though there are no verbs in this short sentence, using señora tells you that any follow-up conversation must use the formal usted form. You would never call someone señora and then use the informal tú with them.

Does con permiso change if I am talking to a friend instead of a señora?