This is a difficult topic to address in a forum such as this. Withdrawals must be expressly stated from the applicant although there is one exception where the bank has approved the applicant and the applicant stops participating.
If the creditor approves the application and the applicant has not inquired within 30 days after applying, the creditor may treat the application as withdrawn and need not comply with the notification requirements of Regulation B. [§1002.9(e)]
A creditor does not have to specifically state "No" for an application to be denied. If the creditor makes a decision to deny the application, then it's a denial. Many times loan officers will say something like "I'm not sure I can get this to go, but if you want to try . . ." That's not encouraging the applicant to proceed and should be seen as a denial.
It may be helpful to study the HMDA Action Taken Codes. Appendix B of the CFPB's Small Entity Compliance Guide for HMDA contains an Action Taken Chart that has various scenarios classified as "Denied," "Withdrawn," etc. This should be helpful in your research on this topic.