Algorithm 3. Update the present policy.

Input: patientID, policyID, policy

Output: Boolean Status

async updatePolicy(ctx, patientID, policyID, policy)

{

$letpolicyAsBytes=awaitctx.stub.getState(patientID);$

$if(!policyAsBytes||policyAsBytes.length==0)\{$

$thrownewError{(}^{\prime }\{patientID\}doesnotexis{t}^{\prime });$

}

$letehrRecord=JSON.parse(policyAsBytes.toString());$

if (!ehrRecord.policies[policyID])

{

$thrownewError(\mathrm{\prime }\{policyId\}doesnotexist‘);$

}

$letupdatedPolicy=JSON.parse(policy);$

$ehrRecord.policies[policyID]=updatedPolicy;$

await ctx.stub.putState(ownerID, Buffer.from(JSON.stringify(ehrRecord)));

return updatedPolicy;

}