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Yes, if you don't call they will not activate the new cards and your present ones will expire and they will be closed. I learned the hard way when I neglected to do so with my BoA card and lost an 8K credit line which affected my debt to credit ratio which caused a chain effect when other cards lowered my limits as a result of this.
Renew them and keep them open, and only use them once in a while for a small transaction here and there and payoff those balances immediately (so they won't close them for inactivity).