Q: iPhone 5 drops call I am on if another caller tries to call me

Hello, Knit7purl7.  

Thank you for visiting Apple Support Communities.  

I understand that your iPhone calls drop when receiving another call.  If you are answering the incoming call, this could be related to call waiting being disabled.  You can check this by going through the menu as outlined below.  Depending on what carrier you have this could be related to a provisioning issue.  If this is the case you will need to reach out to your carrier.  

     

Call waiting

Turn on or off in  Settings > Phone.

 

iPhone: Understanding phone features

http://support.apple.com/en-us/HT202176

Cheers, 

Jason H.  

Knit7purl7, 

No problem at all, I am just glad I could help.  

-Jason H.