Sanchi asked her friend if she remembered the lady they were talking about.
The original direct speech is: "Do you remember the lady we are talking about?" - Sanchi said to her friend.
Identify the reporting verb and tense:
Reporting verb: "said"
Tense: Present simple ("Do" in the original sentence)
Change the pronouns:
Change "you" to "her" to reflect the shift from the second person (direct speech) to the third person (indirect speech).
Change the verb tense:
The present simple tense "Do" changes to the past simple tense "did" in indirect speech.
Rearrange the sentence:
Move the reporting clause (Sanchi said to her friend) to the beginning.
Put the rest of the sentence in the past tense.
Putting it all together, you get: "Sanchi asked her friend if she remembered the lady they were talking about."
The probable complete question is
Change into indirect speech
"Do you remember the lady we are talking about? " Sanchi said to her friend