Verbseoul.
하다 verb
사양하다sayanghadato refuse courteously, to decline

To say to refuse courteously, to decline politely in the present tense, use 사양해요 (sah-yahng-hae-yoh). Below is the full conjugation of 사양하다 across the three tenses and three everyday speech levels.

Conjugation table

TenseCasual (반말)Polite (요)Formal (합니다)
Present
사양해
sah-yahng-hae
사양해요
sah-yahng-hae-yoh
사양합니다
sah-yahng-hahm-nee-dah
Past
사양했어
sah-yahng-hae-ssuh
사양했어요
sah-yahng-hae-ssuh-yoh
사양했습니다
sah-yahng-hae-sseum-nee-dah
Future
사양할 거야
sah-yahng-hahl- -guh-yah
사양할 거예요
sah-yahng-hahl- -guh-yae-yoh
사양할 겁니다
sah-yahng-hahl- -guhm-nee-dah

Other useful forms

Command Polite (세요)
사양하세요
sah-yahng-hah-sae-yoh
Suggestion / Let's Polite (요)
사양해요
sah-yahng-hae-yoh
Question Polite (요)
사양해요?
sah-yahng-hae-yoh-?
Connective “and” — (고)
사양하고
sah-yahng-hah-goh
Conditional “if” — (면)
사양하면
sah-yahng-hah-myuhn
Noun form — (기)
사양함
sah-yahng-hahm