Usually a player feels comfortable with few "positions" (unless he/she is a GM). That's why sometimes it's said that a player should choose and begin to study openings whose outcome results in a position he/she likes.
It's said, for example, that positional players should open with
1. d4, while aggressive players with
1. e4; a Black who chooses Sicilian
1. e4 c5 is more aggressive than one who chooses Caro-Kann, etc.
Are there some lines which allow a single player to change the aggressive or positional path of a game, in order to surprise the opponent?
For example, a Benko Gambit, despite the "positional"
1. d4, is a double-edged opening, but it's chosen by Black whether to play it or not. Is there an aggressive or very tactical opening that White may choose after
Other examples: are there ways, for White, to lead a game to a strategic-positional slow battle when Black chooses a Sicilian Defense? Are there ways for Black to play positionally against a King's Gambit?