How to reinstall phalcon switching from php 7.1 to php 7.2

Hello, I have a trouble using php and phalcon and this is my story. I installed in a server php 7.1 and phalcon 3.4.5 and phalcon-dev-tools in a server with Ubuntu 16.

So, now, we have issues from dependencies installed, in this case is Cross-Origin error header using Twilio, from composer.json file. The only way to resolve this is upgrade php 7.2 (because Twilio doesn't launch error when I was writing code in localhost).

After upgrade php, I create the following files

$ vim /etc/php/7.2/apache2/conf.d/30-phalcon.ini
$ vim /etc/php/7.2/fpm/conf.d/30-phalcon.ini
$ vim /etc/php/7.2/cli/conf.d/30-phalcon.ini

all of them with:

extension=phalcon.so

Then, I delete vendor directory, next I typed composer install to install dependencies from composer.json; and finally, in my console displays the following message:

root@starnet-clks:/var/www/clicksseeker/server# composer install
PHP Warning:  PHP Startup: Unable to load dynamic library 'phalcon.so' (tried: /usr/lib/php/20170718/phalcon.so (/usr/lib/php/20170718/phalcon.so: cannot open shared object file: No such file or directory), /usr/lib/php/20170718/phalcon.so.so (/usr/lib/php/20170718/phalcon.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0
Loading composer repositories with package information
Installing dependencies (including require-dev) from lock file
Your requirements could not be resolved to an installable set of packages.

So, finally, in conclusion, I have to reinstall phalcon from my server and reinstalling again. Someone have a guide with steps to reinstall phalcon and phalcon-dev-tools in ubuntu?

Thanks.

Updated

To update phalcon, I had to go to ~/cphalcon/build directory (This is the phalcon repository downloaded from github cphalcon page, I switch to 3.4.x branch), then I had to type the following command ./install if you doesn't have privileges type sudo ./install.