K V - it's his/your/the conveyancer's choice whether to withdraw an application or not. What's most expedient will depend on what each of you want/need to be able to proceed.
If an application is to be withdrawn then we need that in writing from the applicant and they can request cancellation using
our online contact form
This forum is also HMLR so I'm unsure as to why you would ring also but do appreciate you are trying to resolve matters as swiftly as possible. I would suggest speaking to the owner and conveyancer involved re both applications and agreeing the best way forward as appropriate