partner-contact/partner_tier_validation/views/res_partner_view.xml

<?xml version="1.0" encoding="utf-8" ?>
<!-- Copyright 2019 Open Source Integrators
     License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl). -->
<odoo>

    <record id="partner_form_tier" model="ir.ui.view">
        <field name="name">partner.form.tier</field>
        <field name="model">res.partner</field>
    <field name="inherit_id" ref="base.view_partner_form" />
    <field name="arch" type="xml">
        <xpath expr="/form/sheet" position="before">
              <header>
             <field name="state" widget="statusbar" statusbar_visible="new, approved" />
                 <button
                        name="request_validation"
                        string="Request Validation"
                        attrs="{'invisible': ['|','|',('need_validation', '!=', True),('rejected','=',True),('state','not in',['new','to approve'])]}"
                        type="object"
                    />
                  <button
                        name="restart_validation"
                        string="Restart Validation"
                        attrs="{'invisible': ['|',('review_ids', '=', []),('state','not in',['new','to approve'])]}"
                        type="object"
                    />
               </header>
            </xpath>

        <header position="after">
                <field name="need_validation" invisible="1" />
                <field name="validated" invisible="1" />
        <field name="rejected" invisible="1" />
        <field name="reviewer_ids" invisible="1" />
                <div
                    class="alert alert-warning"
                    role="alert"
                    attrs="{'invisible': ['|', '|', '|',
                     ('validated', '=', True), ('state', 'not in', ['new','to approve']),
                     ('rejected', '=', True), ('review_ids', '=', [])]}"
                    style="margin-bottom:0px;"
                >
                    <p><i class="fa fa-info-circle" />This partner needs to be
                        approved before it can have transactions.
                        <field name="can_review" invisible="1" />
                        <button
                            name="validate_tier"
                            string="Validate"
                            attrs="{'invisible': [('can_review', '=', False)]}"
                            type="object"
                            class="oe_inline oe_button btn-success"
                            icon="fa-thumbs-up"
                        />
                        <button
                            name="reject_tier"
                            string="Reject"
                            attrs="{'invisible': [('can_review', '=', False)]}"
                            type="object"
                            class="btn-icon btn-danger"
                            icon="fa-thumbs-down"
                        />
                    </p>
                </div>
                <div
                    class="alert alert-success"
                    role="alert"
                    attrs="{'invisible': ['|', '|', ('validated', '!=', True), ('state', 'not in', ['new','to approve']), ('review_ids', '=', [])]}"
                    style="margin-bottom:0px;"
                >
                    <p><i class="fa fa-thumbs-up" /> Partner has been <b
                        >approved and now can have transactions</b>!</p>
                </div>
                <div
                    class="alert alert-danger"
                    role="alert"
                    attrs="{'invisible': ['|', '|', ('rejected', '!=', True), ('state', 'not in', ['new','to approve']), ('review_ids', '=', [])]}"
                    style="margin-bottom:0px;"
                >
                    <p><i class="fa fa-thumbs-down" /> Partner creation has been <b
                        >rejected</b>.</p>
                </div>
            </header>
            <xpath expr="//form/div[hasclass('oe_chatter')]" position="before">
                <field
                    name="review_ids"
                    widget="tier_validation"
                    attrs="{'invisible':[('review_ids', '=', [])]}"
                />
            </xpath>

        </field>
    </record>

    <record id="partner_form_tier_filter" model="ir.ui.view">
        <field name="name">partner.form.tier.filter</field>
        <field name="model">res.partner</field>
        <field name="inherit_id" ref="base.view_res_partner_filter" />
        <field name="arch" type="xml">
            <filter name="type_person" position="before">
                <filter
                    name="needs_review"
                    string="Needs my Review"
                    domain="[('reviewer_ids','in',uid), ('state', 'not in', ['approved','to approve'])]"
                    help="Partner(s) to review"
                />
            </filter>
        </field>
    </record>

</odoo>