diff --git a/CHANGELOG b/CHANGELOG
index 152f0196c7..f2f6225810 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,4 @@
+* Permit to edit amount for manual payment in processing
 * Use reference field for statement line relation
 * Do not create dunning for line with pending payment
 * Add support for Python 3.10
diff --git a/payment.py b/payment.py
index 5e0770b0fc..7c86340265 100644
--- a/payment.py
+++ b/payment.py
@@ -305,7 +305,13 @@ class Payment(Workflow, ModelSQL, ModelView):
     date = fields.Date('Date', required=True, states=_STATES, depends=_DEPENDS)
     amount = Monetary(
         "Amount", currency='currency', digits='currency', required=True,
-        states=_STATES, depends=_DEPENDS)
+        states={
+            'readonly': ~Eval('state').in_(
+                If(Eval('process_method') == 'manual',
+                    ['draft', 'processing'],
+                    ['draft'])),
+            },
+        depends=['state', 'process_method'])
     line = fields.Many2One('account.move.line', 'Line', ondelete='RESTRICT',
         domain=[
             ('move.company', '=', Eval('company', -1)),
@@ -405,6 +411,13 @@ class Payment(Workflow, ModelSQL, ModelView):
                     'icon': 'tryton-forward',
                     'depends': ['state'],
                     },
+                'proceed': {
+                    'invisible': (
+                        ~Eval('state').in_(['succeeded', 'failed'])
+                        | (Eval('process_method') != 'manual')),
+                    'icon': 'tryton-back',
+                    'depends': ['state', 'process_method'],
+                    },
                 'succeed': {
                     'invisible': ~Eval('state').in_(
                         ['processing', 'failed']),
@@ -559,6 +572,7 @@ class Payment(Workflow, ModelSQL, ModelView):
             return group
 
     @classmethod
+    @ModelView.button
     @Workflow.transition('processing')
     def proceed(cls, payments):
         assert all(p.group for p in payments)
diff --git a/payment.xml b/payment.xml
index 2e4c7d9ce8..63f97fa98f 100644
--- a/payment.xml
+++ b/payment.xml
@@ -390,6 +390,16 @@ this repository contains the full copyright notices and license terms. -->
             <field name="group" ref="group_payment_approval"/>
         </record>
 
+        <record model="ir.model.button" id="payment_proceed_button">
+            <field name="name">proceed</field>
+            <field name="string">Processing</field>
+            <field name="model" search="[('model', '=', 'account.payment')]"/>
+        </record>
+        <record model="ir.model.button-res.group" id="payment_proceed_button_group_payment">
+            <field name="button" ref="payment_proceed_button"/>
+            <field name="group" ref="group_payment"/>
+        </record>
+
         <record model="ir.model.button" id="payment_succeed_button">
             <field name="name">succeed</field>
             <field name="string">Succeed</field>
diff --git a/view/payment_form.xml b/view/payment_form.xml
index 017ffe827c..bc078a52b7 100644
--- a/view/payment_form.xml
+++ b/view/payment_form.xml
@@ -41,6 +41,7 @@ this repository contains the full copyright notices and license terms. -->
         <group col="-1" colspan="2" id="buttons">
             <button name="draft"/>
             <button name="approve"/>
+            <button name="proceed"/>
             <button name="fail"/>
             <button name="succeed"/>
         </group>