Explanation
-(으)십시오 is the request form of the formal -(스)ㅂ니다 style: -십시오 after a vowel (가다 → 가십시오), -으십시오 after a consonant (앉다 → 앉으십시오). It is the register of announcements, signs, service staff and subordinates addressing a superior; between acquaintances -(으)세요 is the natural choice, and -아/어 주십시오 softens it to a favour. 잠시만 기다리십시오. — Please wait a moment.