have a second string to your bow
have a second string to (one's) bow
To have multiple ways to accomplish something. At least you have a second string to your bow, since you can always contact your aunt if the recruiter from HR doesn't call you back.
have a second string to your bowhave an alternative resource that you can make use of if the first one fails. British
This is a metaphor from archery; related expressions include have several strings to your bow and add another string to your bow. Second string can also be used on its own to mean simply ‘an alternative resource or course of action’.