This app was mentioned in 2 comments, with an average of 2.00 upvotes
https://play.google.com/store/apps/details?id=by.androld.contactsvcf
I use this app, basically you make a vcf file that contains all your contacts and you mail that to yourself or copy it over bluetooth on the other phone. Then you tap the file to import the contacts.
Perhaps your LG contacts app already has the export contacts feature, it will generate a file without the need of the app i linked.
Maybe try Contacts VCF