Hey, You can Use an Alternate Email Id. Follow these steps -
1- Firstly Go to the Yahoo Login Page i.e. https://login.yahoo.com 2- Enter Your Yahoo Email id and Click on "Next"
3- On next Page Tap on " I forgot my Password"
4-Now they will ask to send Verification on Mobile Number over there you need to click "I do not have Access to this Phone".
5-Now the Page will Redirect to https://io.help.yahoo.com/contact (Yahoo help visitor Page)
6- Tap on "See product-related help articles"
7-Now Click on "Sign-in Helper"
8- Now Enter another email id for Recovery"
9-Where you will get the security code
10-enter that security code and reset your password
or still, have any doubt, post back.