Partly related to: "changing subject and verb position..."
Related to original, direct questions, there are 2 types of them, depending on the beginning they have:
a) Question word/phrase + aux. + subject + main verb...
Ex. **WHERE** DOES HE LIVE ?( int.simple pres.)
b) Aux.+ subject +main verb...?
Ex. **Did** he know the answer?
Trying to be more polite, you may use varied introductions to the questions above,(ex. Tell me../ I don't know../ Can you tell me...etc) what produces a change in the order and case of the original question:
Ex. a)Can you tell me where he lives?(Interrog.S.Present)
" **Q.W.** + S +(AFF. SIMPLE PRESENT)
After the introduction, the question word is repeated, immediately followed by the subject and then the verb(s)..in the original affirm. tense.
Ex. b) Did he know the answer? (interrog. simple past)
Tell me **IF** he knew the answer. (affirm simple past)
**IF** + S + (AFF.S.P.)...
In case b), we need an extra word to introduce the question after the introductory "Tell me..."(IF or WHETHER), IMMEDIATELY following the SUBJECT and next, the verb(s).
As you can see, interrogative tenses change to affirmative ones, when you use an introductory expression before.
Since SIMPLE PRESENT AFFIRMATIVE and SIMPLE PAST AFFIRMATIVE **do not take the** **auxiliary in the affirmative form,**(DO/DOES/DID). They disappear when you use an expression before the question.
All other tenses always use the auxiliary in aff./interrog. and negative cases.
DO/DOES and DID might appear in affirm SIMPLE PRESENT and SIMPLE PAST when you want to emphasize the action, so nothing doing with embedded questions, title the previous questions receive.