“Could I have a week to think it over?”
Think something over means to consider it carefully before deciding. Compared with think about, it suggests taking time to reach a conclusion. Frank asks for a week to decide.
B1-39 / CEFR B1 / EPISODE 39
Clarifying a promotion and asking for time to decide
SceneFrank is meeting his boss about a promotion. He has opened his notebook and is taking notes.

WORDS & CONTEXT
Think something over means to consider it carefully before deciding. Compared with think about, it suggests taking time to reach a conclusion. Frank asks for a week to decide.
Pros and cons are the advantages and disadvantages considered in a decision. The phrase comes from Latin pro, for, and contra, against.