Entity Connection String at run-time

Following is useful

Public Shared Function GetRunTimeEntityConnectionString(EntityConnectionStringName As String) As String
Dim currentConString = Configuration.ConfigurationManager.ConnectionStrings(EntityConnectionStringName).ConnectionString
Dim builder As New EntityClient.EntityConnectionStringBuilder(currentConString)
builder.ProviderConnectionString = <“NewConString”>
‘builder.Metadata = “res://*/LookupModel.csdl|res://*/LookupModel.ssdl|res://*/LookupModel.msl”
‘builder.Provider = “System.Data.SqlClient”
Return builder.ConnectionString
End Function

Usage
Dim EntityConnectionString = RuntimeConnectionString.GetRunTimeEntityConnectionString(<EntityConStringName>)
context = New <Namespace>.EntityModel.<EntityName>Entities(EntityConnectionString)

If trying to change actual SharedApp.config as follows then currently get an error.
Configuration.ConfigurationManager.ConnectionStrings(<“Name of Entity ConString”>).ConnectionString = RunTimeEntityConnectionString
Error:
system.configuration.configurationerrorsexception the configuration is read only

There are suggested methods for solving this online