How to withdraw application

Hi dear members
I would like to know one of my friend she is British passport holder , she has recently applied for her partners extension thorough solicitor in suppose visa . For some personal reasons she would like to withdraw application for him . She have few questions about it if some can help her .
Can she withdraw application on behalf of her partner although they have applied through solicitor or she has to ask solicitor to do it.
Can she simply call home office and ask for the documents to be returned on her home address ( which have to be update with them as currently solicitor address is the correspondence address .

I'm not sure if I have been able to put across her question properly . I'm sorry but they are no more togahter and she wish to cancel his extension application which had not been decided as biometric had not been done yet . In biometric it says that if you don't do your bio matric your application will be rejected . Now she wants to know if she can cancel the application will she get her fee back which she has paid from her own account and secondly if she ask for the withdrawal of the application will they send the passport of her partner. Thirdly previously corespondence had been done though solicitor can she call and tell them to stop any more corespondence to soliciter onwards and directly send her on her home address .

Dear zimba
Thnxxx for the quick reply . Can you please advise what can be best course of action for her .